Safety and tolerability of available urate-lowering drugs: a critical review

Therapeutic Activity of Green Tea Epigallocatechin-3-Gallate on Metabolic Diseases and Non-Alcoholic Fatty Liver Diseases: The Current Updates

Green tea polyphenols have numerous functions including antioxidation and modulation of various cellular proteins and are thus beneficial against metabolic diseases including obesity, type 2 diabetes, cardiovascular and non-alcoholic fatty liver diseases, and their comorbidities. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea and is attributed to antioxidant and free radical scavenging activities, and the likelihood of targeting multiple metabolic pathways. It has been shown to exhibit anti-obesity, anti-inflammatory, anti-diabetic, anti-arteriosclerotic, and weight-reducing effects in humans. Worldwide, the incidences of metabolic diseases have been escalating across all age groups in modern society. Therefore, EGCG is being increasingly investigated to address the problems. This review presents the current updates on the effects of EGCG on metabolic diseases, and highlights evidence related to its safety. Collectively, this review brings more evidence for therapeutic application and further studies on EGCG and its derivatives to alleviate metabolic diseases and non-alcoholic fatty liver diseases.

Identification of 5-[5-cyano-1-(pyridin-2-ylmethyl)-1H-indole-3-carboxamido] thiazole-4-carboxylic acid as a promising dual inhibitor of urate transporter 1 and xanthine oxidase

In combination with allopurinol, tranilast is used as an urate transporter 1 (URAT1) inhibitor for the treatment of hyperuricemia, but its structure-activity relationship concerning URAT1 inhibitory activity is rarely studied. In this paper, analogs 1-30 were designed and synthesized using scaffold hopping strategy on the basis of tranilast and the privileged scaffold indole. Then, URAT1 activity was evaluated using ¹⁴C-uric acid uptake assay with HEK293-URAT1 overexpressing cells. Compared with tranilast (inhibitory rate = 44.9% at 10 μM), most compounds displayed apparent inhibitory effects, ranging from 40.0% to 81.0% at 10 μM on URAT1. Surprisingly, along with the bringing in of a cyano group at the 5-position of indole ring, compounds 26 and 28-30 exerted xanthine oxidase (XO) inhibitory activity. In particular, compound 29 presented potency on URAT1 (48.0% at 10 μM) and XO (IC₅₀ = 1.01 μM). Molecular simulation analysis revealed that the basic structure of compound 29 had an affinity with URAT1, and XO. Furthermore, compound 29 demonstrated a significant hypouricemic effect in a potassium oxonate-induced hyperuricemia rat model at an oral dose of 10 mg/kg during in vivo tests. In summary, tranilast analog 29 was identified as a potent dual-target inhibitor of URAT1 and XO, and a promising lead compound for further investigation.

Amelioration effects of α-viniferin on hyperuricemia and hyperuricemia-induced kidney injury in mice

BACKGROUND

α-Viniferin, the major constituent of the roots of Caragana sinica (Buc'hoz) Rehder with a trimeric resveratrol oligostilbenoid skeleton, was demonstrated to possess a strong inhibitory effect on xanthine oxidase in vitro, suggesting it to be a potential anti-hyperuricemia agent. However, the in vivo anti-hyperuricemia effect and its underlying mechanism were still unknown.

PURPOSE

The current study aimed to evaluate the anti-hyperuricemia effect of α-viniferin in a mouse model and to assess its safety profile with emphasis on its protective effect on hyperuricemia-induced renal injury.

METHODS

The effects were assessed in a potassium oxonate (PO)- and hypoxanthine (HX)-induced hyperuricemia mice model by analyzing the levels of serum uric acid (SUA), urine uric acid (UUA), serum creatinine (SCRE), serum urea nitrogen (SBUN), and histological changes. Western blotting and transcriptomic analysis were used to identify the genes, proteins, and signaling pathways involved.

RESULTS

α-Viniferin treatment significantly reduced SUA levels and markedly mitigated hyperuricemia-induced kidney injury in the hyperuricemia mice. Besides, α-viniferin did not show any obvious toxicity in mice. Research into the mechanism of action of α-viniferin revealed that it not only inhibited uric acid formation by acting as an XOD inhibitor, but also reduced uric acid absorption by acting as a GLUT9 and URAT1 dual inhibitor as well as promoted uric acid excretion by acting as a ABCG2 and OAT1 dual activator. Then, 54 differentially expressed (log₂ FPKM ≥ 1.5, p ≤ 0.01) genes (DEGs) repressed by the treatment of α-viniferin in the hyperuricemia mice were identified in the kidney. Finally, gene annotation results revealed that downregulation of S100A9 in the IL-17 pathway, of CCR5 and PIK3R5 in the chemokine signaling pathway, and of TLR2, ITGA4, and PIK3R5 in the PI3K-AKT signaling pathway were involved in the protective effect of α-viniferin on the hyperuricemia-induced renal injury.

CONCLUSIONS

α-Viniferin inhibited the production of uric acid through down-regulation of XOD in hyperuricemia mice. Besides, it also down-regulated the expressions of URAT1 and GLUT9 and up-regulated the expressions of ABCG2 and OAT1 to promote the excretion of uric acid. α-Viniferin could prevent hyperuricemia mice from renal damage by regulating the IL-17, chemokine, and PI3K-AKT signaling pathways. Collectively, α-viniferin was a promising antihyperuricemia agent with desirable safety profile. This is the first report of α-viniferin as an antihyperuricemia agent.

U-shaped association of serum uric acid with cardiovascular disease risk scores and the modifying role of sex among Chinese adults

BACKGROUND AND AIMS

Serum uric acid (SUA) is involved in the development of cardiovascular disease (CVD). However, information on the dose-response relationship between SUA and CVD is limited in the Chinese population. This study aimed to investigate the potential nonlinear dose-response association of SUA with CVD risk in a Chinese population and to explore the effect of sex on these associations.

METHODS AND RESULTS

Cross-sectional data, from 6252 Chinese adults aged 30-74 years who participated in the China Health and Nutrition Survey 2009, were stratified by SUA deciles. The 10-year risk of CVD was determined using the Framingham risk score. A restricted cubic spline (RCS) was incorporated into the logistic models to assess the nonlinear relationship between SUA and CVD. Among the participants, 65%, 20%, and 15% had low, moderate, and high 10-year CVD risks, respectively. Compared with the reference SUA strata of 225 to <249 μmol/L, CVD risk was significantly increased at SUA ≥294 μmol/L, with adjusted ORs ranging from 2.39 (1.33-4.33) to 4.25 (2.37-7.65). An increasingly higher nonsignificant CVD risk was found at SUA <225 μmol/L and showed a nonlinear U-shaped association. In the fitted RCS model, an approximate U-shaped association between SUA and CVD risk scores was found in women, but this significant nonlinear relationship was not found in men.

CONCLUSION

This study showed that both lower and higher SUA levels were associated with a higher 10-year CVD risk among Chinese adults, forming a U-shaped relationship, and this pattern was particularly pronounced for women.

Individualized Homeopathic Medicines in Treatment of Hyperuricemia: Evaluation by Double-Blind, Randomized, Placebo-Controlled Trial

INTRODUCTION

Hyperuricemia (HU) is a major health issue in India and across the globe. It increases the disease burden and hampers quality of life. This study was aimed at exploring the effects of individualized homeopathic medicines (IHMs) against placebo in the treatment of HU.

METHODS

This double-blind, randomized, placebo-controlled trial was conducted on 60 patients suffering from HU in the outpatient department of D. N. De Homoeopathic Medical College and Hospital, Kolkata. Each patient received either IHMs or identical-looking placebos, along with advice on dietary modifications irrespective of codes. Serum uric acid (SUA) level was the primary outcome measure; the HU quality of life questionnaire (HUQLQ) and the Measure Yourself Medical Outcome Profile version 2 (MYMOP-2) were the secondary outcomes; all measured at baseline, and every month, up to 3 months. Group differences were examined by two-way (split-half) repeated-measures analysis of variance after adjusting for baseline differences. Significance level was set at p ≤0.05, two-tailed.

RESULTS

The intention-to-treat sample (n = 58) was analyzed. Between-group differences in SUA levels (F 1, 56 = 13.833, p <0.001), HUQLQ scores (F 1, 56 = 32.982, p <0.001) and MYMOP-2 profile scores (F 1, 56 = 23.873, p <0.001) were statistically significant, favoring IHMs against placebos, with medium to large effect sizes. Calcarea carbonica and Pulsatilla nigricans were the most frequently prescribed medicines. No serious adverse events were reported from either of the groups.

CONCLUSION

IHMs showed significantly better results than placebos in reducing SUA levels and improving quality of life in patients suffering from HU.

TRIAL REGISTRATION

CTRI/2019/10/021503; UTN: U1111-1241-1431.

Purine Metabolism Dysfunctions: Experimental Methods of Detection and Diagnostic Potential

Purines, such as adenine and guanine, perform several important functions in the cell. They are found in nucleic acids; are structural components of some coenzymes, including NADH and coenzyme A; and have a crucial role in the modulation of energy metabolism and signal transduction. Moreover, purines have been shown to play an important role in the physiology of platelets, muscles, and neurotransmission. All cells require a balanced number of purines for growth, proliferation, and survival. Under physiological conditions, enzymes involved in purines metabolism maintain a balanced ratio between their synthesis and degradation in the cell. In humans, the final product of purine catabolism is uric acid, while most other mammals possess the enzyme uricase that converts uric acid to allantoin, which can be easily eliminated with urine. During the last decades, hyperuricemia has been associated with a number of human extra-articular diseases (in particular, the cardiovascular ones) and their clinical severity. In this review, we go through the methods of investigation of purine metabolism dysfunctions, looking at the functionality of xanthine oxidoreductase and the formation of catabolites in urine and saliva. Finally, we discuss how these molecules can be used as markers of oxidative stress.

The evidence from clinical trials on Gout medicines effect on COVID-19: A protocol for systematic review and meta-analysis

AIM

To evaluate the available evidence from clinical trials on the efficacy of gout medicines against COVID-19.

DESIGN

Systematic review and Meta-analysis.

METHODS

We are systematically searching five databases [PubMed, Embase, CT.gov, ICTRP, CINAHL (EBSCO)]. We are following the PRISMA statement and the EPOC guidelines. The meta-analysis will be conducted using Revman-5.4.1 from Cochrane collaboration, UK. This review's protocol was also registered in PROSPERO, University of York, UK (CRD42022299718).

RESULTS

In this meta-analysis, we plan to give a conclusive overview of the available evidence on the efficacy of the medications used to manage gout in reducing COVID-19 mortality, ICU admission, ventilation rate and hospitalization duration. If the results were positive, these drugs would greatly add to the scarce treatment options against COVID-19. Furthermore, these drugs might provide an excellent alternative to inconvenient and expensive drugs. Additionally, most of these drugs have a well-established safety profile for use during nursing, making them a much safer option for nursing mothers with COVID-19.

Drug repurposing for cardiovascular diseases: New targets and indications for probenecid

The available pharmacological options in the management of cardiovascular diseases such as ischaemic heart disease and subsequent heart failure are effective in slowing the progression of this condition. However, the long-term prognosis is still poor, raising the demand for new therapeutic strategies. Drug repurposing is a time- and cost-effective drug development strategy that offers approved and abandoned drugs a new chance for new indications. Recently, drugs used for the management of gout-related inflammation such as canakinumab or colchicine have been considered for drug repurposing in cardiovascular indications. The old uricosuric drug, probenecid, has been identified as a novel therapeutic option in the management of specific cardiac diseases as well. Probenecid can modulate myocardial contractility and vascular tone and exerts anti-inflammatory properties. The mechanisms behind these beneficial effects might be related inhibition of inflammasomes, and to modulation purinergic-pannexin-1 signalling and TRPV2 channels, which are recently identified molecular targets of probenecid. In this review, we provide an overview on repurposing probenecid for ischaemic heart disease and subsequent heart failure by summarizing the related experimental and clinical data and propose its potential repurposing to treat cardiovascular diseases.

Mechanism of Xiezhuo Huayu Yiqi Tongluo Formula in the Treatment of Uric Acid Nephropathy Based on Network Pharmacology, Molecular Docking, and In Vivo Experiments

Background

Xiezhuo Huayu Yiqi Tongluo Formula (XHYTF) consists of 14 Chinese herbal medicines. In this study, we investigated the potential mechanism of XHYTF in the treatment of uric acid nephropathy (UAN) through network pharmacology, molecular docking, and in vivo methods.

Methods

Using various pharmacological databases and analysis platforms, information on the active ingredients and targets of Chinese herbal medicine was collected, and UAN disease targets were retrieved using OMIM, Gene Cards, and NCBI. Then common target proteins were integrated. A Drug-Component-Target (D-C-T) map was constructed to screen core compounds and build a protein-protein interaction (PPI) network. Further, Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for common targets, and a Drug-Component-Target-Pathway (D-C-T-P) network diagram was constructed. The molecular docking simulation was performed to verify the binding affinity between core components and hub targets. Subsequently, the UAN rat model was established, followed by the collection of serum and renal tissues. The expression levels of indicators in the serum were determined using an enzyme-linked immunosorbent assay. The pathological changes of renal tissues were detected using H & E staining and Masson staining. The expression of related proteins in renal tissue was detected by western blot.

Results

In the study, 216 active ingredients and 439 targets in XHYTF were screened, and 868 targets were identified as being related to UAN. Among them, 115 were common targets. Based on the D-C-T network, quercetin, luteolin, β-sitosterol, and stigmasterol were observed to be the key active ingredients of XHYTF that were effective against UAN. The analysis of the PPI network revealed TNF, IL6, AKT1, PPARG, and IL1β as the 5 key targets. GO enrichment analysis revealed that the pathways were mainly concentrated in cell killing, regulation of signaling receptor activity, and other activities. Subsequently, KEGG pathway analysis revealed that multiple signaling pathways, including the HIF-1, PI3K-Akt, IL-17, and other signaling pathways, were closely related to the action of XHYTF. All 5 key targets were confirmed to interact with all core active ingredients. In vivo experiments indicated that XHYTF significantly reduced blood uric acid and creatinine levels, alleviated inflammatory cell infiltration in kidney tissues, reduced the levels of serum inflammatory factors such as TNF-α and IL1β, and ameliorated renal fibrosis in rats with UAN. Finally, western blot revealed decreased levels of PI3K and AKT1 proteins in the kidney, which confirmed the hypothesis.

Conclusion

Collectively, our observations demonstrated that XHYTF significantly protects kidney function, including alleviation of inflammation and renal fibrosis via multiple pathways. This study provided novel insights into the treatment of UAN using traditional Chinese medicines.

Exploration of the anti-hyperuricemia effect of TongFengTangSan (TFTS) by UPLC-Q-TOF/MS-based non-targeted metabonomics

BACKGROUND

TongFengTangSan (TFTS) is a commonly used Tibetan prescription for gout treatment. Previously, TFTS (CF) was confirmed to have a significant uric acid-lowering effect. However, the anti-hyperuricemia mechanisms and the main active fractions remain unclear. The current study aimed to investigate the anti-hyperuricemia mechanism using metabolomics and confirm the active CF fraction.

METHODS

The hyperuricemia model was established through intraperitoneal injection containing 100 mg/kg potassium oxonate and 150 mg/kg hypoxanthine by gavage. We used serum uric acid (sUA), creatinine (CRE), blood urea nitrogen (BUN), xanthine oxidase (XOD) activity, interleukin-6 (IL-6) and interleukin-1β (IL-1β) as indicators to evaluate the efficacy of CF and the four fractions (SX, CF30, CF60, and CF90). The anti-hyperuricemia mechanism of CF was considered through non-targeted metabolomics depending on the UPLC-Q-TOF-MS technology. Principle component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) helped explore the potential biomarkers in hyperuricemia. Moreover, the differential metabolites and metabolic pathways regulated by CF and four fractions were also assessed.

RESULTS

CF revealed a significant anti-hyperuricemia effect by down-regulating the level of sUA, sCRE, sIL-1β, and XOD. SX, CF30, CF60, and CF90 differed in the anti-hyperuricemia effect. Only CF60 significantly lowered the sUA level among the four fractions, and it could be the main efficacy fraction of TFTS. Forty-three differential metabolites were identified in hyperuricemia rats from plasma and kidney. Pathway analysis demonstrated that seven pathways were disrupted among hyperuricemia rats. CF reversed 19 metabolites in hyperuricemia rats and exerted an anti-hyperuricemia effect by regulating purine metabolism. CF60 was the main active fraction of TFTS and exerted a similar effect of CF by regulating purine metabolism.

CONCLUSIONS

CF and CF60 could exert an anti-hyperuricemia effect by regulating the abnormal purine metabolism because of hyperuricemia while improving intestinal and renal function. CF60 could be the main active fraction of TFTS.

A randomized pilot trial assessing the reduction of gout episodes in hyperuricemic patients by oral administration of Ligilactobacillus salivarius CECT 30632, a strain with the ability to degrade purines

Introduction

Hyperuricemia and gout are receiving an increasing scientific and medical attention because of their relatively high prevalence and their association with relevant co-morbidities. Recently, it has been suggested that gout patients have an altered gut microbiota. The first objective of this study was to investigate the potential of some Ligilactobacillus salivarius strains to metabolize purine-related metabolites. The second objective was to evaluate the effect of administering a selected potential probiotic strain in individuals with a history of hyperuricemia.

Methods

Inosine, guanosine, hypoxanthine, guanine, xanthine, and uric acid were identified and quantified by high-performance liquid chromatography analysis. The uptake and biotransformation of these compounds by a selection of L. salivarius strains were assessed using bacterial whole cells and cell-free extracts, respectively. The efficacy of L. salivarius CECT 30632 to prevent gout was assessed in a pilot randomized controlled clinical trial involving 30 patients with hyperuricemia and a history of recurrent gout episodes. Half of the patients consumed L. salivarius CECT 30632 (9 log₁₀ CFU/day; probiotic group; n = 15) for 6 months while the remaining patients consumed allopurinol (100-300 mg/daily; control group; n = 15) for the same period. The clinical evolution and medical treatment received by the participants were followed, as well as the changes in several blood biochemical parameters.

Results

L. salivarius CECT 30632 was the most efficient strain for inosine (100%), guanosine (100%) and uric acid (50%) conversion and, therefore, it was selected for the pilot clinical trial. In comparison with the control group, administration of L. salivarius CECT 30632 resulted in a significant reduction in the number of gout episodes and in the use of gout-related drugs as well as an improvement in some blood parameters related to oxidative stress, liver damage or metabolic syndrome.

Conclusion

Regular administration of L. salivarius CECT 30632 reduced serum urate levels, the number of gout episodes and the pharmacological therapy required to control both hyperuricemia and gout episodes in individuals with a history of hyperuricemia and suffering from repeated episodes of gout.

A Drug-Drug Interaction Study of a Novel Selective Urate Reabsorption Inhibitor, SHR4640, and Xanthine Oxidase Inhibitor, Febuxostat, in Patients With Primary Hyperuricemia

SHR4640 is a novel, selective urate reabsorption inhibitor. As the mode of action of SHR4640 differs from that of a xanthine oxidase inhibitor, such as febuxostat, coadministration of these drugs may be a treatment option for patients with primary hyperuricemia. We assessed the potential drug-drug interaction between SHR4640 and febuxostat. In this single-center, open-label, randomized, drug-drug interaction study, subjects received 80 mg febuxostat or 10 mg SHR4640 alone daily in the first week, whereas during the second week a combination of SHR4640 and febuxostat was administered daily to all subjects. Plasma concentrations of SHR4640 and febuxostat were analyzed. We compared their pharmacokinetic and pharmacodynamic parameters and assessed both safety and tolerability. Compared with febuxostat alone, the geometric mean ratios (90%CIs) of the maximum concentration (C_max ) and the area under the plasma concentration-time curve over the dosing interval τ (AUC_0-τ ) for febuxostat after coadministration were 1.284 (1.016 to 1.621) and 0.984 (0.876 to 1.106), respectively. The geometric mean ratios (90%CIs) of C_max and AUC_0-τ for SHR4640 after coadministration compared with SHR4640 alone were 0.910 (0.839 to 0.988) and 0.929 (0.893 to 0.966), respectively. Febuxostat had no effect on SHR4640 pharmacokinetic parameters, as the 90%CIs of the geometric mean ratios were all within the range of 0.80 to 1.25. The coadministration of febuxostat and SHR4640 was well tolerated. The coadministration of SHR4640 with febuxostat was not associated with any clinically relevant pharmacokinetic drug interactions. SHR4640 combined with febuxostat had a synergistic effect on reducing uric acid in the pharmacodynamics, with the AUC decreasing from 7440 to 3170 h μmol/L compared with febuxostat alone and from 5730 to 2960 h μmol/L compared with SHR4640 alone.

Hypouricemic and nephroprotective effects of palmatine from Cortex Phellodendri Amurensis: A uric acid modulator targeting Keap1-Nrf2/NLRP3 axis

ETHNOPHARMACOLOGICAL RELEVANCE

Palmatine (Pal) is a major bioactive alkaloid originated from ancient Chinese herbal medicine Cortex Phellodendri Amurensis (CPA), which has long been applied to treat hyperuricemia (HUA)-related diseases. Pal possesses potent anti-inflammatory and anti-oxidant effects against metabolic diseases. However, its potential beneficial effect against PO (potassium oxonate)/HX (hypoxanthine)-induced HUA remains elusive.

AIM OF THE STUDY

This study aimed to investigate the potential pharmacological effect and mechanism of Pal on PO/HX-induced HUA in mice.

MATERIAL AND METHODS

A mouse model of HUA was established by co-administration of PO/HX once daily for 7 consecutive days. The HUA mice were orally given three doses (25, 50 and 100 mg/kg) of Pal daily for a week. Febuxostat (Feb, 5 mg/kg) was given as a positive control. At the scheduled termination of the experiment, the whole blood, liver and kidney were collected for subsequent analyses. The concentrations of uric acid (UA), creatinine (CRE) and blood urea nitrogen (BUN), and activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) were evaluated. Histopathological alterations of the kidney were detected by H&E staining. The inflammatory and oxidative stress status was detected by assay kits. Additionally, key proteins involved in the urate transporter, Keap1-Nrf2 and TXNIP/NLRP3 signaling pathways were evaluated by immunohistochemistry and Western blotting. Finally, molecular docking was employed to probe the binding characteristics of Pal and target proteins Keap1, NLRP3, URAT1 and HO-1.

RESULTS

Administration of Pal substantially decreased the elevated kidney weight, lowered UA, CRE and BUN levels, and attenuated abnormal histopathological alterations. Meanwhile, treatment with Pal also dramatically lowered hepatic XOD and ADA activities. Besides, Pal treatment effectively mitigated the renal inflammatory and oxidative stress markers. Further mechanistic investigation indicated Pal distinctly downregulated the protein levels of GLUT9 and URAT1, while up-regulated the expression levels of OAT1 and ABCG2. Pal also restored Nrf2 activation, promoted subsequent expression of anti-oxidative enzymes, and downregulated the expressions of TXNIP, NLRP3, apoptosis-associated speck-like (ASC), caspase-1, IL-1β and IL-18. Molecular docking analysis also indicated Pal firmly bound with Keap1, NLRP3, URAT1 and HO-1.

CONCLUSIONS

These findings indicated that Pal exhibited favorable anti-HUA effect via modulating the expressions of transporter-related proteins and suppressing XOD activity. Furthermore, Pal also alleviated HUA-induced kidney injury, which was at least partially related to restoring Keap1-Nrf2 pathway and inhibiting TXNIP/NLRP3 inflammasome. Our investigation was envisaged to provide experimental support for the traditional application of CPA and CPA-containing classical herbal formulas in the management of HUA-related diseases and might provide novel dimension to the clinical application of Pal.

Anti-Hyperuricemic, Nephroprotective, and Gut Microbiota Regulative Effects of Separated Hydrolysate of α-Lactalbumin on Potassium Oxonate- and Hypoxanthine-Induced Hyperuricemic Mice

SCOPE

This study aims to investigate the anti-hyperuricemic and nephroprotective effects and the potential mechanisms of the separated gastrointestinal hydrolysates of α-lactalbumin on hyperuricemic mice.

METHODS AND RESULTS

The gastrointestinal hydrolysate of α-lactalbumin, the hydrolysate fraction with molecular weight (MW) < 3 kDa (LH-3k), and the fragments with smallest MW among LH-3K harvested through dextran gel chromatography (F5) are used. Hyperuricemia mice are induced via daily oral gavage of potassium oxonate and hypoxanthine. F5 displays the highest in vitro xanthine oxidase (XO) inhibition among all the fractions separated from LH-3k. Oral administration of F5 significantly reduces the levels of serum uric acid (UA), creatinine, and urea nitrogen. F5 treatment could ameliorate kidney injury through alleviating oxidative stress and inflammation. F5 alleviates hyperuricemia in mice by inhibiting hepatic XO activity and regulating the expression of renal urate transporters. Gut microbiota analysis illustrates that F5 administration increases the abundance of some SCFAs producers, and inhibits the growth of hyperuricemia and inflammation associated genera. LH-3k exhibits similar effects but does not show significance as those of the F5 fraction.

CONCLUSION

The anti-hyperuricemia and nephroprotective functions of F5 are mediated by inhibiting hepatic XO activity, ameliorating oxidative stress and inflammation, regulating renal urate transporters, and modulating the gut microbiota in hyperuricemic mice.

Wuling San Based on Network Pharmacology and in vivo Evidence Against Hyperuricemia via Improving Oxidative Stress and Inhibiting Inflammation

Background

Hyperuricemia (HUA) is a major public health issue with a high prevalence worldwide. Wuling San (WLS) is an effective treatment for HUA. However, the active compounds and the related mechanism are unclear. In this study, we aimed to explore the active compounds and the underlying pharmacological mechanisms of WLS against HUA.

Methods

First, a network pharmacology approach was used to detect active compounds of WLS, and potential targets and signaling pathways involved in the treatment of HUA were predicted. Then, a molecular docking strategy was used to predict the affinity between active compounds and key targets. Finally, to verify the prediction, the HUA rat model was established.

Results

49 active compounds with 108 common targets were obtained. Besides, cerevisterol, luteolin, ergosterol peroxide, beta-sitosterol, and sitosterol were identified as key active compounds. In PPI analysis, TNF, IL6, CASP3, PPARG, STAT3, and other 12 core targets were obtained. GO enrichment analysis indicated that WLS was likely to interfere with oxidative stress in the treatment of HUA, and KEGG enrichment analysis indicated multiple inflammation-related signaling pathways possibly involved in the treatment of HUA by WLS, including TNF, and NOD-like receptor, HIF-1, PI3K-Akt, and IL-17 signaling pathways. The results of molecular docking indicated that the active compounds had good binding properties to their key targets. In the validation experiments, WLS significantly reduced the levels of serum uric acid (SUA) and serum malondialdehyde (MDA). Moreover, WLS not only significantly increased the levels of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD), but also inhibited the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).

Conclusion

In the present study, we demonstrate that WLS has multicomponent, multitarget, and multi-pathway properties in the treatment of HUA. Its potential capability to reduce SUA could be ascribed to oxidative stress improvement and inflammation inhibition.

Comparative efficacy and safety of uricosuric agents in the treatment of gout or hyperuricemia: a systematic review and network meta-analysis

OBJECTIVES

The current world witnesses a greatly increased prevalence and incidence of hyperuricemia and gout with unfortunately the comparative efficacy and safety of present available uricosuric agents remaining uncertain. We herein aimed to investigate the most appropriate uricosuric agent for gout or hyperuricemia patients.

METHOD

PubMed, Embase, Cochrane Library databases, and ClinicalTrials.gov from inception to 2 July 2022 were searched to retrieve eligible studies assessing efficacy and safety of uricosuric drugs in hyperuricemia or gout patients. Network meta-analysis was carried out using the Stata 16.0 software.

RESULTS

Twelve randomized controlled trials comprising 1851 patients were eventually included. Network meta-analysis showed that dotinurad 4 mg once daily, verinurad, dotinurad 2 mg once daily, dotinurad 1 mg once daily, and benzbromarone were the top 5 effective treatments to achieve target serum uric acid. Furthermore, dotinurad 4 mg once daily was more effective at achieving urate-lowering targets (RR of dotinurad 4 mg once daily vs. probenecid: 1.68, 95% CI [1.13; 2.50]) and safer (RR of probenecid vs. dotinurad 4 mg once daily: 1.77, 95% CI [0.69; 4.56]) than probenecid.

CONCLUSIONS

This network meta-analysis demonstrated an important absolute benefit of dotinurad 4 mg once daily to achieve target serum uric acid and low risk of adverse events for drug treatment of gout or hyperuricemia patients. Additionally, verinurad might be used as an alternative uricosuric therapeutic option to dotinurad. These findings provided further comprehensive insight into the treatment value of current uricosuric agents for gout or hyperuricemia. Key Points 1. This is the first systematic review and network meta-analysis examining the efficacy and safety of currently available uricosuric agents in gout or hyperuricemia patients. 2. Recommended doses of dotinurad 4mg once daily used for the treatment of gout or hyperuricemia patients can significantly decrease serum uric acid levels. 3. The present findings will provide further comprehensive insight into the treatment value of certain uricosuric agents for gout or hyperuricemia.

Xanthine oxidase inhibitory potentials of flavonoid aglycones of Tribulus terrestris: in vivo, in silico and in vitro studies

Background

Despite the ongoing safety-driven spate of flavonoid xanthine oxidase (XOD) inhibition investigations, there is a lack of flavonoid-based uricostatic antihyperuricemic agents in clinical medicine. The poor pharmacokinetic profiles of glycosides (the natural form of existence of most flavonoids) relative to their aglycones could be largely responsible for this paradox. This investigation was aimed at providing both functional and molecular bases for the possible discovery of XOD inhibitory (or uricostatic) anti-hyperuricemic flavonoid aglycones from the leaves of a flavonoid-rich medicinal plant, Tribulus terrestris. To this end, the flavonoid aglycone fraction of T. terrestris leaf extract (FATT) was evaluated in vivo for antihyperuricemic activity in ethanol-induced hyperuricemic mice, monitoring serum and liver uric acid levels. Molecular docking and molecular dynamics simulation studies were carried out on the three major flavonoid aglycones of T. terrestris (isorhamnetin, quercetin and kaempferol) against an inhibitor conformation XOD model. The three flavonoids were also subjected to in vitro XOD activity assay, comparing their IC50 to that of allopurinol, a standard uricostatic antihyperuricemic drug.

Results

FATT significantly lowered serum uric acid (p < 0.0001) and liver uric acid (p < 0.05) levels of the experimental animals, implying anti-hyperuricemic activity with uricostatic action mechanism allusions. Molecular docking studies revealed high binding affinity values (− 7.8, − 8.1, − 8.2 kcal/mol) for the aglycones (isorhamnetin, quercetin and kaempferol, respectively). Radius of gyration and RMSD analyses of the molecular dynamics simulation trajectories of the three aglycone–XOD complexes revealed substantial stability, the highest stability being demonstrated by the kaempferol–XOD complex. In vitro XOD activity assay showed kaempferol (IC50: 8.2 ± 0.9 μg/ml), quercetin (IC50: 20.4 ± 1.3 μg/ml) and isorhamnetin (IC50: 22.2 ± 2.1 μg/ml) to be more potent than allopurinol (IC50: 30.1 ± 3.0 μg/ml).

Conclusion

This work provides a scientific basis for the use of T. terrestris in the treatment of hyperuricemia-related (e.g. kidney stone and gout) disorders. It also provides the molecular basis for a focussed screening of the flavonoid aglycones chemical space for the possible discovery of flavonoid-based uricostatic anti-hyperuricemic drugs or drug templates.

Design, synthesis and activity evaluation of novel lesinurad analogues containing thienopyrimidinone or pyridine substructure as human urate transporter 1 inhibitors

Urate Transporter 1 (URAT1) plays a crucial role in uric acid transport, making it an attractive target for the treatment of gout and hyperuricemia. As a representative URAT1 inhibitor, Lesinurad treat gout by promoting the uric acid excretion. However, its lower in vitro and in vivo activity should be highly attracted attention. Herein, the bioisosterism, molecular hybridization and scaffold hopping strategies were exploited to modify all the structural components of Lesinurad and finally thirty novel compounds bearing thienopyrimidinone or pyridine core were obtained. Most of the compounds displayed certain URAT1 inhibitory activity in vitro. Among them, thienopyrimidinones 6 (IC50 = 7.68 μM), 10 (IC50 = 7.56 μM), 14 (IC50 = 7.31 μM) and 15 (IC50 = 7.90 μM) showed slightly better potency than positive control Lesinurad (IC50 = 9.38 μM). Notably, 10 also displayed inhibitory activity (IC50 = 55.96 μM) against GLUT9. Additionally, in vivo serum uric acid (SUA)-lowering experiments were performed on some representative compounds and it was revealed that all the selected compounds could decrease the SUA level in mice, of which the decrease rate of SUA was 73.29% for the most promising compound 10, significantly greater than that of Lesinurad (26.89%). Meanwhile, the preliminary SARs based on the URAT1 inhibitory activity were discussed in detail, which pointed out the direction for further structural optimization. Overall, the thienopyrimidinone and pyridine are prospective skeletons for the developing novel URAT1 inhibitors with considerable potential for optimization.

Citrus Bergamia and Cynara Cardunculus Reduce Serum Uric Acid in Individuals with Non-Alcoholic Fatty Liver Disease

Background and Objectives: Hyperuricemia and liver steatosis are risk factors for cardiovascular diseases and mortality. The use of natural compounds could be a safe and effective alternative to drugs for the treatment of fatty liver and hyperuricemia. Polyphenolic fraction of Citrus Bergamia in association with the extract of Cynara Cardunculus, as nutraceutical, is able to reduce body weight, hepatic steatosis and markers of oxidative stress. Then, we performed a secondary analysis of a double-blind placebo-controlled trial to examine the effects of this nutraceutical on serum uric acid levels in adults with fatty liver. Materials and Methods: The study included 94 individuals with hepatic steatosis. For six weeks, the intervention group was given a nutraceutical (300 mg/day) comprising a Bergamot polyphenol fraction and Cynara Cardunculus extract. The control group received a daily pill of placebo. Serum uric acid, lipids, glucose and anthropometric parameters were assessed at baseline and after 6 weeks. Results: We found a greater reduction in serum uric acid in the participants taking the nutraceutical rather than placebo (−0.1 ± 0.7 mg/dL vs. 0.3 ± 0.7 mg/dL, p = 0.004), and especially in those with moderate/severe hepatic steatosis also after adjustment for confounding variables. In addition, we analysed the two groups according to tertiles of uric acid concentration. Among participants taking the nutraceutical, we found in those with the highest baseline serum uric acid (>5.4 mg/dL) the greater reduction compared to the lowest baseline uric acid (−7.8% vs. +4.9%; adjusted p = 0.04). The stepwise multivariable analysis confirmed the association between the absolute serum uric acid change and nutraceutical treatment (B = −0.43; p = 0.004). Conclusions: A nutraceutical containing bioactive components from bergamot and wild cardoon reduced serum uric acid during 6 weeks in adults with fatty liver. Future investigations are needed to evaluate the efficacy of this nutraceutical in the treatment of hyperuricaemia.

Insoluble Fiber in Barley Leaf Attenuates Hyperuricemic Nephropathy by Modulating Gut Microbiota and Short-Chain Fatty Acids

Hyperuricemia (HUA), characterized by abnormal serum uric acid (UA) levels, is recognized as an important risk factor for hyperuricemic nephropathy (HN), which is strongly linked to gut microbiota. This study investigated the protective effects and regulatory mechanisms of insoluble fiber from barley leaves (BL) against HN, induced by adenine (Ad) and potassium oxonate (PO). The results showed that BL dramatically reduced the levels of serum UA and creatinine (CR) and alleviated renal injury and fibrosis. Moreover, BL modulated oxidative stress and downregulated the expression of urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys of mice with HN. In addition, the 16S rRNA sequence data showed that BL also increased the relative abundance of short-chain fatty acids (SCFAs)-producing bacteria, including Bacteroides, Alloprevotella, and Eisenbergiella. Besides, BL treatment also increased SCFAs levels. Of interest, the application of SCFAs in hyperuricemic mice effectively reduced their serum UA. Furthermore, SCFAs dose-dependently inhibited URAT1 and GLUT9 in vitro and potently interacted with URAT1 and GLUT9 in the docking analysis. When taken together, our results indicate that BL and its metabolite SCFAs may be potential candidates for relieving HUA or HN.

A Brief Review of Natural Products with Urate Transporter 1 Inhibition for the Treatment of Hyperuricemia

Hyperuricemia is a common disease caused by a high level of uric acid. Urate transporter 1 (URAT1) is an important protein and mediates approximately 90% of uric acid reabsorption. Therefore, the URAT1 inhibitor is a class of uricosuric medicines widely used in the clinic for the treatment of hyperuricemia. To find the new medicine with stronger URAT1 inhibition and lower toxicity, researchers have been exploring natural products. This study systematically summarizes the natural products with URAT1 inhibition. The results show that many natural products are potential URAT1 inhibitors, such as flavonoids, terpenoids, alkaloids, coumarins, stilbenes, and steroids, among which flavonoids are the most promising source of URAT1 inhibitors. It is worth noting that most studies have focused on finding natural products with inhibition of URAT1 and have not explored their activities and mechanisms toward URAT1. By reviewing the few existing studies of the structure-activity relationship and analyzing common features of natural products with URAT1 inhibition, we speculate that the rigid ring structure and negative charge may be the keys for natural products to produce URAT1 inhibition. In conclusion, natural products are potential URAT1 inhibitors, and exploring the mechanism of action and structure-activity relationship will be an important research direction in the future.

Potential role of tea drinking in preventing hyperuricaemia in rats: biochemical and molecular evidence

BACKGROUND

Lifestyle and diet play a significant role in hyperuricaemia. Accumulating evidence indicates that tea consumption is associated with hyperuricaemia and gout. However, diverse compounds in different types of tea make it quite difficult to determine the relevant molecular mechanism. Here, we compared the effects of six types of tea on hyperuricaemia induced by potassium oxonate (PO) and hypoxanthine in rats and investigated the possible underlying mechanisms.

METHODS

Rats were randomly assigned to ten groups: the control, hyperuricaemia model, benzbromarone positive control, traditional Chinese medicine Simiao San positive control, green tea, yellow tea, black tea, white tea, red tea, and cyan tea treatment groups. After 21 days, uric acid (UA), xanthine oxidase (XOD), alanine aminotransferase (ALT),blood urea nitrogen (BUN), and creatinine (CRE) were assessed. Serum levels of interleukin-1β (IL-1β) were measured with an enzyme-linked immunosorbent assay. Haematoxylin-eosin staining and immunohistochemistry were used to assess liver and kidney injury.

RESULTS

The levels of UA, CRE, and BUN in the treatment group were decreased to varying degrees. There was a significant reduction in UA, CRE, and BUN levels for yellow tea compared to the positive control drugs. Yellow tea suppressed XOD activity and alleviated hepatic and kidney injury. Network pharmacology and untargeted metabolomics indicated that ten yellow tea bioactive ingredients and 35 targets were responsible for preventing hyperuricaemia, which was mediated by 94 signalling pathways, including IL-1β and TNF.

CONCLUSION

These findings indicate that green tea cannot reduce the serum uric acid level of hyperuricaemic rats. Yellow tea can significantly improve hyperuricaemia by regulating the inflammatory response, autophagy, and apoptosis. This study provides a potential candidate for the treatment of hyperuricaemia and a basis for selecting therapeutic tea for patients with hyperuricaemia.

An integrated study of Shenling Baizhu San against hyperuricemia: Efficacy evaluation, core target identification and active component discovery

ETHNOPHARMACOLOGICAL RELEVANCE

Shenling Baizhu San (SLBZ) is a famous Traditional Chinese Medicine (TCM) formula that strengthens the spleen for replenishing qi, removing dampness, and inducing diuresis to relieve diarrhea. Combining the TCM interpretation that dampness is a vital pathogenesis factor in hyperuricemia occurrence and development, SLBZ has excellent potential against hyperuricemia from the perspective of TCM theories.

AIM OF THE STUDY

This study aimed to investigate the efficacy of SLBZ against hyperuricemia and its possible mechanism with emphasis on the active components and the core targets.

MATERIALS AND METHODS

In the present study, we employed meta-analysis and a hyperuricemia quail model to evaluate the uric acid-lowering effect of SLBZ. Bodyweight, serum uric acid, and excreta uric acid levels in quails were assessed. Subsequently, we analyzed the potential active components and core targets of SLBZ against hyperuricemia by network pharmacology and calculated their interaction using molecular docking. Furthermore, the hyperuricemia rats treated with interfering agents of core targets were established to determine the central role of selected targets in hyperuricemia progression. Besides, we isolated and characterized the primary renal tubular epithelial cells of quails to verify the active components and core targets of SLBZ against hyperuricemia. Western blotting was used to observe the expression of core targets treated with active components under the stimulation of interfering agents.

RESULTS

Data from meta-analysis and animal experiments showed that SLBZ could work effectively against hyperuricemia. Hyperuricemia quails treated with SLBZ displayed significantly reduced serum uric acid levels accompanied by increased excretion of uric acid. According to network pharmacology and molecular docking results, 34 potential active components and the core target peroxisome proliferator-activated receptor gamma (PPARγ) for SLBZ against hyperuricemia were identified. The decreased serum uric acid levels in hyperuricemia rats treated with rosiglitazone, an agonist of PPARγ, confirms the essential role of PPARγ in the pathological process of hyperuricemia. Moreover, we first successfully isolated and characterized the primary renal tubular epithelial cells of quails and observed enhanced phosphorylation of PPARγ at Ser273 in cells handled with high-level uric acid. Whereas, the enhanced expression of p-PPARγ Ser273 could be down-regulated by luteolin and naringenin, two active components of SLBZ against hyperuricemia.

CONCLUSION

In summary, SLBZ is a promising anti-hyperuricemia agent, and luteolin and naringenin are the active components for SLBZ against hyperuricemia by down-regulating phosphorylation of PPARγ at Ser273.

Review of Urate-Lowering Therapeutics: From the Past to the Future

We reviewed all currently available ULT, as well as any medications in development using following databases: United States Food and Drug Administration (FDA), European Medicines Agency (EMA), Japanese Pharmaceutical and Medical Devices Agency (PMDA), and ClinicalTrials.gov. We identified a total of 36 drugs, including 10 approved drugs, 17 in clinical testing phases, and 9 in preclinical developmental phases. The 26 drugs currently undergoing testing and development include 5 xanthine oxidase inhibitors, 14 uricosurics, 6 recombinant uricases, and one with multiple urate-lowering mechanisms of action. Herein, we reviewed the benefit and risk of each drug summarizing currently available drugs. New trials of uricosuric agents are underway to develop the new indication. New drugs are going on to improve the potency of recombinant uricase and to develop the new route administration of such as oral formulation. This review will provide valuable information on the properties, indications, and limitations of ULTs.

Traditional Chinese herbs and natural products in hyperuricemia-induced chronic kidney disease

Hyperuricemia is a common biochemical disorder, which resulted from both excessive uric acid (UA) production and/or absolute or relative impairment of urinary UA excretion. Growing evidence has indicated that hyperuricemia is an independent risk factor for the development and progression of chronic kidney disease (CKD), causing hyperuricemia-induced CKD (hyperuricemic nephropathy, HN). The therapeutic strategy of HN is managing hyperuricemia and protecting kidney function. Adverse effects of commercial drugs make persistent treatment of HN challenging. Traditional Chinese medicine (TCM) has exact efficacy in lowering serum UA without serious adverse effects. In addition, TCM is widely applied for the treatment of CKD. This review aimed to provide an overview of efficacy and mechanisms of traditional Chinese herbs and natural products in hyperuricemia-induced CKD.

Allopurinol attenuates repeated traumatic brain injury in old rats: A preliminary report

Traumatic brain injury (TBI) is an overlooked cause of morbidity, which was shown to accelerate inflammation, oxidative stress, and neuronal cell loss and is associated with spatial learning and memory impairments and some psychiatric disturbances in older adults. However, there is no effective treatment in order to offer a favorable outcome encompassing a good recovery after TBI in older adults. Hence, the present study aimed to investigate the histological and neurobehavioral effects of Allopurinol (ALL) in older rats that received repeated TBI (rTBI). For this purpose, a weight-drop rTBI model was used on old male Wistar rats. Rats received 5 repeated TBI/sham injuries 24 h apart and were treated with saline or Allopurinol 100 mg/kg, i.p. each time. They were randomly assigned to three groups: control group (no injury); rTBI group (received 5 rTBI and treated with saline); rTBI+ALL group (received 5 rTBI and treated with Allopurinol). Then, half of the animals from each group were sacrificed on day 6 and the remaining animals were assessed with Open field, Elevated plus maze and Morris Water Maze test. Basic neurological tasks were evaluated with neurological assessment protocol every other day until after the 19th day from the last injury. Brain sections were processed for neuronal cell count in the hippocampus (CA1), dentate gyrus (DG), and prefrontal cortex (PC). Also, an immunohistochemical assay was performed to determine NeuN, iNOS, and TNFα levels in the brain regions. The number of neurons was markedly reduced in CA1, GD, and PC in rats receiving saline compared to those receiving allopurinol treatment. Immunohistochemical analysis showed marked induction of iNOS and TNFα expression in the brain tissues which were reduced after allopurinol at 6 and 19 days post-injury. Also, ALL-treated rats demonstrated a remarkable induce in NeuN expression, indicating a reduction in rTBI-induced neuronal cell death. In neurobehavioral analyses, time spent in closed arms, in the corner of the open field, swimming latency, and distance were impaired in injured rats; however, all of them were significantly improved by allopurinol therapy. To sum up, this study demonstrated that ALL may mitigate rTBI-induced damage in aged rats, which suggests ALL as a potential therapeutic strategy for the treatment of recurrent TBI.

Usefulness of Optimized Human Fecal Material in Simulating the Bacterial Degradation of Sulindac and Sulfinpyrazone in the Lower Intestine

The first aim of this study was to evaluate the usefulness of optimized human fecal material in simulating sulforeductase activity in the lower intestine by assessing bacterial degradation of sulindac and sulfinpyrazone, two sulforeductase substrates. The second aim was to evaluate the usefulness of drug degradation half-life generated in simulated colonic bacteria (SCoB) in informing PBPK models. Degradation experiments of sulfinpyrazone and of sulindac in SCoB were performed under anaerobic conditions using recently described methods. For sulfinpyrazone, the abundance of clinical data allowed for construction of a physiologically based pharmacokinetic (PBPK) model and evaluation of luminal degradation clearance determined from SCoB data. For sulindac, the availability of sulindac sulfide and sulindac sulfone standards allowed for evaluating the formation of the main metabolite, sulindac sulfide, during the experiments in SCoB. Both model compounds degraded substantially in SCoB. The PBPK model was able to adequately capture exposure of sulfinpyrazone and its sulfide metabolite in healthy subjects, in ileostomy and/or colectomy subjects, and in healthy subjects pretreated with metoclopramide by implementing degradation half-lives in SCoB to calculate intrinsic colon clearance. Degradation rates of sulindac and formation rates of sulindac sulfide in SCoB were almost identical, in line with in vivo data suggesting the sulindac sulfide is the primary metabolite in the lower intestine. Experiments in SCoB were useful in simulating sulforeductase related bacterial degradation activity in the lower intestine. Degradation half-life calculated from experiments in SCoB is proven useful for informing a predictive PBPK model for sulfinpyrazone.

Long-Term Effect of Febuxostat on Endothelial Function in Patients With Asymptomatic Hyperuricemia: A Sub-Analysis of the PRIZE Study

Background

Xanthine oxidase is involved in the production of uric acid and the generation of superoxide anion. We evaluated the long-term effect of febuxostat, a non-purine selective xanthine oxidase inhibitor, on endothelial function in patients with asymptomatic hyperuricemia.

Methods

In the PRIZE study, patients with hyperuricemia were randomly assigned to either add-on febuxostat treatment (febuxostat group) or non-pharmacologic hyperuricemia treatment (control group). Among the 514 participants, endothelial function was assessed in 41 patients in the febuxostat group and 38 patients in the control group by flow-mediated vasodilation (FMD) of the brachial artery at the beginning of the study and after 12 and/or 24 months of treatment (63 men; median age, 68.0 years).

Results

The least squares mean concentration of serum uric acid was significantly lower in the febuxostat group than in the control group at 6 months (mean between-group difference [febuxostat group - control group], -2.09 mg/dL [95% confidence interval (CI), -2.520 to -1.659]; P < 0.001), 12 months (mean between-group difference, -2.28 mg/dL [95% CI, -2.709 to -1.842]; P < 0.001), and 24 months (mean between-group difference, -2.61 mg/dL [95% CI, -3.059 to -2.169]; P < 0.001). No significant differences were found between groups in the least squares mean estimated percentage change in FMD at 12 months (mean between-group difference, -0.56% [95% CI, -1.670 to 0.548]; P = 0.319) and at 24 months (mean between-group difference, -0.60% [95% CI, -1.886 to 0.685]; P = 0.357).

Conclusion

Febuxostat treatment did not alter endothelial function assessed by FMD during a 2-year study period in patients with asymptomatic hyperuricemia.

Blockade of Autophagy Prevents the Progression of Hyperuricemic Nephropathy Through Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Hyperuricemia has become a common metabolic disease, and is a risk factor for multiple diseases, including chronic kidney disease. Our recent study indicated that following persistent uric acid stimulation, autophagy was activated in rats of hyperuricemic nephropathy (HN) and facilitated the development of renal fibrosis. Nevertheless, the potential mechanism by which autophagy promoted the progression of HN is still not fully elucidated. Thus, in the current study, we investigated the mechanisms of autophagy inhibition on the development of HN. Our data showed that autophagy was activated in human renal tubular cell lines (HK-2) exposure to uric acid. Inhibition of autophagy with 3-methyladenine (3-MA) and transfected with Beclin-1 siRNA prevented uric acid-induced upregulation of α-SMA, Collagen I and Collagen III in HK-2 cells. Moreover, uric acid upregulated autophagy via promoting the p53 pathway. In vivo, we showed that hyperuricemic injury induced the activation of NLRP3 inflammasome and pyroptosis, as evidenced by cleavage of caspase-1 and caspase-11, activation of gasdermin D (GSDMD) and the release of IL-1β and IL-18. Treatment with autophagy inhibitor 3-MA alleviated aforementioned phenomenon. Stimulation with uric acid in HK-2 cells also resulted in NLRP3 inflammasome activation and pyroptotic cell death, however treatment with 3-MA prevented all these responses. Mechanistically, we showed that the elevation of autophagy and degradation of autophagolysosomes resulted in the release of cathepsin B (CTSB), which is related to the activation of NLRP3 inflammasome. CTSB siRNA can inhibit the activation of NLRP3 inflammasome and pyroptosis. Collectively, our results indicate that autophagy inhibition protects against HN through inhibiting NLRP3 inflammasome-mediated pyroptosis. What’s more, blockade the release of CTSB plays a crucial role in this process. Thus, inhibition of autophagy may be a promising therapeutic strategy for hyperuricemic nephropathy.

Engineered Escherichia coli Nissle 1917 with urate oxidase and an oxygen-recycling system for hyperuricemia treatment

Hyperuricemia is the second most prevalent metabolic disease to human health after diabetes. Only a few clinical drugs are available, and most of them have serious side effects. The human body does not have urate oxidase, and uric acid is secreted via the kidney or the intestine. Reduction through kidney secretion is often the cause of hyperuricemia. We hypothesized that the intestine secretion could be enhanced when a recombinant urate-degrading bacterium was introduced into the gut. We engineered an Escherichia coli Nissle 1917 strain with a plasmid containing a gene cassette that encoded two proteins PucL and PucM for urate metabolism from Bacillus subtilis, the urate importer YgfU and catalase KatG from E. coli, and the bacterial hemoglobin Vhb from Vitreoscilla sp. The recombinant E. coli strain effectively degraded uric acid under hypoxic conditions. A new method to induce hyperuricemia in mice was developed by intravenously injecting uric acid. The engineered Escherichia coli strain significantly lowered the serum uric acid when introduced into the gut or directly injected into the blood vessel. The results support the use of urate-degrading bacteria in the gut to treat hyperuricemia. Direct injecting bacteria into blood vessels to treat metabolic diseases is proof of concept, and it has been tried to treat solid tumors.

The Role of the Intestine in the Development of Hyperuricemia

Gout is a common inflammatory arthritis caused by the deposition of sodium urate crystals in the joints. Hyperuricemia is the fundamental factor of gout. The onset of hyperuricemia is related to purine metabolism disorders or uric acid excretion disorders. Current studies have shown that the intestine is an important potential organ for the excretion of uric acid outside the kidneys. The excretion of uric acid of gut is mainly achieved through the action of uric acid transporters and the catabolism of intestinal flora, which plays an important role in the body’s uric acid balance. Here we reviewed the effects of intestinal uric acid transporters and intestinal flora on uric acid excretion, and provide new ideas for the treatment of hyperuricemia and gout.

Comparison of Benzbromarone and Allopurinol on Primary Prevention of the First Gout Flare in Asymptomatic Hyperuricemia

Objectives. Whether uric acid-lowering agent use in asymptomatic hyperuricemia can reduce the development of the first gout flare remains unsettled. The goal of the present research was to test the efficacy of benzbromarone and allopurinol on primary prevention of the first gout flare in persons with asymptomatic hyperuricemia in Taiwan. Methods. One observational cohort study was constructed to examine the 2001−2015 dataset adapted from the National Health Insurance Program of Taiwan containing the claims data of 2 million beneficiaries. Asymptomatic hyperuricemia was considered as individuals on uric acid-lowering therapy who did not have gout flares. Individuals aged 20−84 without gout flares who had the use of benzbromarone alone were assigned into a benzbromarone group. Individuals ages 20−84 without gout flares who had the use of allopurinol alone were assigned into an allopurinol group. The final study included 6111 pairs of 1:1 propensity score-matched individuals from both benzbromarone and allopurinol groups. The end point was assigned as individuals who were newly diagnosed with their first gout flare. The incidence rate of the first gout flare was estimated between the benzbromarone and allopurinol groups. A Cox proportional hazards regression model was applied to explore the hazard ratio and 95% confidence interval of the first gout flare related to benzbromarone use and allopurinol use. Results. The incidence rate of the first gout flare was lower in the benzbromarone group compared with an allopurinol group (3.29 versus 5.46 per 1000 person-months, incidence rate ratio = 0.60 and 95% confidence interval = 0.56−0.64). After adjustment for co-variables, the adjusted hazard ratio of the first gout flare was 0.63 (95% confidence interval = 0.59−0.68, p < 0.001) for the benzbromarone group when compared with the allopurinol group. Conclusion. People with asymptomatic hyperuricemia taking benzbromarone have a lower hazard of developing their first gout flare when compared with those taking allopurinol. Based on the medication safety, the therapeutic effects and the low price, with oral administration once daily, we suggest that benzbromarone should be the first drug of choice if clinicians are treating asymptomatic hyperuricemia.

Washed microbiota transplantation reduces serum uric acid levels in patients with hyperuricaemia

BACKGROUND

Previous studies have found that hyperuricaemia (HUA) is closely related to intestinal flora imbalance.

AIM

The current study investigated the effects and safety of washed microbiota transplantation (WMT) on serum uric acid (SUA) levels in different populations.

METHODS

A total of 144 patients who received WMT from July 2016 to April 2020 in the First Affiliated Hospital of Guangdong Pharmaceutical University and had SUA data before treatment were selected. Changes in SUA levels before and after treatment were retrospectively reviewed based on short-term and mid-term effects of WMT regimens. SUA levels measured in the last test within 3 mo after the first WMT represented the short-term effect, and SUA levels measured in the last test within 3-6 mo after the first WMT represented the mid-term effect. The patients were divided into an HUA group (SUA > 416 μM) and a normal uric acid (NUA) group (SUA ≥ 202 μM to ≤ 416 μM) based on pretreatment SUA levels.

RESULTS

Average short-term SUA levels in the HUA group decreased after WMT (481.00 ± 99.85 vs 546.81 ± 109.64 μM, n = 32, P < 0.05) in 25/32 patients and returned to normal in 10/32 patients. The short-term level of SUA reduction after treatment moderately correlated with SUA levels before treatment (r = 0.549, R² = 0.300, P < 0.05). Average SUA levels decreased after the first and second courses of WMT (469.74 ± 97.68 vs 540.00 ± 107.16 μM, n = 35, and 465.57 ± 88.88 vs 513.19 ± 78.14 μM, n = 21, P < 0.05). Short-term and mid-term SUA levels after WMT and SUA levels after the first, second and third courses of WMT were similar to the levels before WMT in the NUA group (P > 0.05). Only 1/144 patients developed mild diarrhea after WMT.

CONCLUSION

WMT reduces short-term SUA levels in patients with HUA with mild side effects but has no obvious effect on SUA levels in patients with NUA.

Influence of probenecid on endoxifen systemic exposure in breast cancer patients on adjuvant tamoxifen treatment

Introduction:

In breast cancer patients treated with the anti-estrogen tamoxifen, low concentrations of the active metabolite endoxifen are associated with more disease recurrence. We hypothesized that we could increase endoxifen concentrations by induction of its formation and inhibition of its metabolism by co-administration of probenecid.

Methods:

We conducted a crossover study and measured endoxifen concentrations in patients on steady-state tamoxifen monotherapy and after 14 days of combination treatment with probenecid. Eleven evaluable patients were included.

Results:

Treatment with tamoxifen and probenecid resulted in a 26% increase of endoxifen area under the plasma concentration–time curve from 0 to 24 h (AUC_0–24h) compared to tamoxifen monotherapy (95% confidence interval [CI]: 8–46%; p < 0.01), while the maximum observed endoxifen concentration increased with 24% (95% CI: 7–44%; p < 0.01). The metabolic ratio of endoxifen to tamoxifen increased with 110% (95% CI: 82–143%; p < 0.001) after the addition of probenecid.

Conclusion:

Probenecid resulted in a clinically relevant increase of endoxifen concentrations in breast cancer patients treated with adjuvant tamoxifen. This combination therapy could provide a solution for patients with a CYP2D6-poor metabolizer phenotype or endoxifen concentrations below the threshold despite earlier tamoxifen dose.

Repurposing Probenecid to Inhibit SARS-CoV-2, Influenza Virus, and Respiratory Syncytial Virus (RSV) Replication

Viral replication and transmissibility are the principal causes of endemic and pandemic disease threats. There remains a need for broad-spectrum antiviral agents. The most common respiratory viruses are endemic agents such as coronaviruses, respiratory syncytial viruses, and influenza viruses. Although vaccines are available for SARS-CoV-2 and some influenza viruses, there is a paucity of effective antiviral drugs, while for RSV there is no vaccine available, and therapeutic treatments are very limited. We have previously shown that probenecid is safe and effective in limiting influenza A virus replication and SARS-CoV-2 replication, along with strong evidence showing inhibition of RSV replication in vitro and in vivo. This review article will describe the antiviral activity profile of probenecid against these three viruses.

A Phase I, Randomized, Single-Ascending-Dose, Multiple-Dose, and Food-Effect Trial of the Safety, Efficacy, and Pharmacokinetics of Topiroxostat in Healthy Chinese Participants

Background: As the structure of the human diet changes, the prevalence of hyperuricemia is increasing each year. Hyperuricemia and its comorbidities, such as gout, severely affect quality of life. Moreover, hyperuricemia causes renal impairment and is associated with chronic kidney disease. Topiroxostat, a selective xanthine oxidoreductase inhibitor, has been approved to treat hyperuricemia or gout in Japan. Topiroxostat has shown good tolerance and efficacy in the Japanese population. However, its pharmacokinetic (PK) characteristics, efficacy, and safety in the Chinese population remains unknown.Objective: This trial evaluated the PK profile, safety, efficacy, and food effects of Topiroxostat in healthy Chinese participants.Methods: The major endpoint was determination of the PK profile of Topiroxostat. Topiroxostat concentrations were detected with LC-MS/MS. PK parameters were calculated in Phoenix WinNonlin 8.1. Minor endpoints were safety and efficacy assessments. Assessment of adverse events and safety was performed by clinicians. Plasma uric acid concentration (&#x0394;ECmax and &#x0394;AUEC) was determined as the pharmacodynamic index. This study consisted of three arms: single ascending dose (20, 40, and 80 mg, N &#x003D; 10), multiple dose (80 mg BID, 7 days, N &#x003D; 10), and food effects (40 mg single dose, fasting-fed cross-over design, N &#x003D; 10).Results: In the single-ascending-dose arm, Topiroxostat showed rapid absorption and excretion, with Tmax &#x003C;1.6 h and T1/2 2.49&#x2013;3.72 h. Additionally, Topiroxostat showed a wide distribution, on the basis of moderate Vz/F (242.8&#x2013;336.36 L). The main PK parameters Cmax, AUC0-t, and AUC0-C showed a linear relationship with dose (R2 &#x003D; 0.5146, 0.8416, 0.8386, respectively). In the multiple-dose arm, no significant differences were observed in Cmin on days 3&#x2013;6 (P &#x003D; 0.265). No serious adverse events were observed. Regarding efficacy, plasma uric acid levels were controlled to low levels during multiple-dose administration. In the food-effects arm, the fed group showed a lower Cmax than the fasting group (316.00 &#x00B1; 135.81 vs. 478.40 &#x00B1; 175.42 ng/mL, P &#x003D; 0.033) but demonstrated better efficacy (&#x0394;ECmax, P &#x003C; 0.001; &#x0394;AUEC, P &#x003C; 0.001).Conclusions: Topiroxostat showed rapid absorption and a broad distribution in healthy Chinese adults. Additionally, it showed good safety and tolerance in the Chinese population. Moreover, the pharmacodynamic profile indicated that post cibum administration increased the efficacy of Topiroxostat.

CDER167, a dual inhibitor of URAT1 and GLUT9, is a novel and potent uricosuric candidate for the treatment of hyperuricemia

Urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) are important targets for the development of uric acid-lowering drugs. We previously showed that the flexible linkers of URAT1 inhibitors could enhance their potency. In this study we designed and synthesized CDER167, a novel RDEA3710 analogue, by introducing a linker (methylene) between the naphthalene and pyridine rings to increase flexibility, and characterized its pharmacological and pharmacokinetics properties in vitro and in vivo. We showed that CDER167 exerted dual-target inhibitory effects on both URAT1 and GLUT9: CDER167 concentration-dependently inhibited the uptake of [14C]-uric acid in URAT1-expressing HEK293 cells with an IC50 value of 2.08 ± 0.31 μM, which was similar to that of RDEA3170 (its IC50 value was 1.47 ± 0.23 μM). Using site-directed mutagenesis, we demonstrated that CDER167 might interact with URAT1 at S35 and F365. In GLUT9-expressing HEK293T cells, CDER167 concentration-dependently inhibited GLUT9 with an IC50 value of 91.55 ± 15.28 μM, whereas RDEA3170 at 100 μM had no effect on GLUT9. In potassium oxonate-induced hyperuricemic mice, oral administration of CDER167 (10 mg·kg-1 · d-1) for 7 days was more effective in lowering uric acid in blood and significantly promoted uric acid excretion in urine as compared with RDEA3170 (20 mg·kg-1 · d-1) administered. The animal experiment proved the safety of CDER167. In addition, CDER167 displayed better bioavailability than RDEA3170, better metabolic stability and no hERG toxicity at 100 μM. These results suggest that CDER167 deserves further investigation as a candidate antihyperuricemic drug targeting URAT1 and GLUT9.

Untargeted metabolomics reveal the therapeutic effects of Ermiao wan categorized formulas on rats with hyperuricemia

ETHNOPHARMACOLOGICAL RELEVANCE

Ermiao wan (2 MW) is one of the most frequently prescription in traditional Chinese medicine (TCM) to treat hyperuricemia. Sanmiao wan (3 MW) and Simiao wan (4 MW), two modified Ermiao wan, also show good clinical effects in the treatment of gout and hyperuricemia. However, their uric acid lowering effects and potential action mechanism still need to be systematically investigated.

AIM OF THE STUDY

The aim of present study was to analyze and compare the uric acid-lowering effects of 2 MW, 3 MW and 4 MW in rat with high fructose combined with potassium oxonate (HFCPO)-induced hyperuricemia and their possible mechanisms through plasma metabolomics methods.

MATERIALS AND METHODS

HFCPO-induced hyperuricemia rat model was established to evaluate the therapeutic effects of Ermiao wan categorized formulas (ECFs, including 2 MW, 3 MW and 4 MW). Body weight, blood uric acid, creatinine, urine uric acid and urine creatinine levels and histopathological parameters of rats were assessed. Plasma untargeted metabolomics based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was established to collect the metabolic profiles of rats and explore the metabolic changes that occurred after each ECFs treatment.

RESULTS

Oral administration of ECFs could decrease the level of blood uric acid, creatinine and increase the level of urine uric acid and urine creatinine in varying degrees, and alleviated hepatocyte steatosis and atrophy and degeneration of glomerulus, vacuolar degeneration of renal tubular epithelial cells in HFCPO-induced hyperuricemia rats. Plasma untargeted metabolomics analysis showed that significant alterations were observed in metabolic signatures between the HFCPO-induced hyperuricemia group and control group. Thirty five potential biomarkers in rat plasma were identified in the screening by principal component analysis (PCA), partial least squares discrimination analysis (PLS-DA) and orthogonal partial least squares discrimination analysis (OPLS-DA). Differential metabolites related to hyperuricemia, including acylcarnitines and amino acid related metabolites, were further used to indicate relevant pathways in hyperuricemia rats, including tryptophan metabolism, arginine biosynthesis, purine metabolism, arginine and proline metabolism, beta-alanine metabolism, citrate cycle (TCA cycle), glycerophospholipid metabolism and linoleic acid metabolism. 2 MW, 3 MW and 4 MW could invert the pathological process of hyperuricemia to varying degrees through in part regulating the perturbed lipid metabolic pathway. 4 MW were better than 2 MW and 3 MW in the intervention of the disordered tricarboxylic acid metabolism and purine metabolism caused by hyperuricemia.

CONCLUSION

In summary, ECFs treatment could effectively alleviate symptoms of hyperuricemia and regulate metabolic disorders in HFCPO-induced hyperuricemia rats.

Berberrubine attenuates potassium oxonate- and hypoxanthine-induced hyperuricemia by regulating urate transporters and JAK2/STAT3 signaling pathway

Phellodendri Chinensis Cortex (PC) is a traditional medicinal material used to treat gout and hyperuricemia (HUA) in China. Berberine (BBR), the main component of PC, possesses anti-hyperuricemic and anti-gout effects. However, BBR exhibits low bioavailability due to its extensive metabolism and limited absorption. Thus, the metabolites of BBR are believed to be the potential active forms responsible for its in vivo biological activities. Berberrubine (BRB), one of the major metabolites of BBR, exhibits appreciable biological activities even superior to BBR. In this work, the anti-hyperuricemic efficacy of BRB was investigated in HUA model mice induced by co-administration with intraperitoneal potassium oxonate (PO) and oral hypoxanthine (HX) for 7 days. Results showed that administration with BRB (6.25, 12.5, and 25.0 mg/kg) significantly decreased the serum levels of uric acid (UA) by 49.70%, 75.35%, and 75.96% respectively, when compared to the HUA group. In addition, BRB sharply decreased the levels of blood urea nitrogen (BUN) (by 19.62%, 28.98%, and 38.72%, respectively) and serum creatinine (CRE) (by 16.19%, 25.07%, and 52.08%, respectively) and reversed the PO/HX-induced renal histopathological damage dose-dependently. Additionally, BRB lowered the hepatic XOD activity, downregulated the expressions of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1), upregulated expressions of organic anion transporter 1/3 (OAT1/3) and ATP-binding cassette transporter subfamily G member 2 (ABCG2) at both protein and mRNA levels, and suppressed the activation of the JAK2/STAT3 signaling pathway. In addition, BRB significantly decreased the levels of inflammatory mediators (IL-1β, IL-6, and TNF-α). In conclusion, our study indicated that BRB exerted anti-hyperuricemic effect, at least in part, via regulating the urate transporter expressions and suppressing the JAK2/STAT3 signaling pathway. BRB was believed to be promising for further development into a potential therapeutic agent for HUA treatment.

Antihyperuricemia and antigouty arthritis effects of Persicaria capitata herba in mice

BACKGROUND

Hyperuricemia (HUA) is an important risk factor for gout, renal dysfunction and cardiovascular diseases. The whole plant of Persicaria capitata (Buch.-Ham. ex D. Don) H. Gross, namely Persicaria capitata herba, is a well-known ethnic herb with potent therapeutic effects on urinary tract infections and urinary calculus, yet previous reports have only focused on its effect on urinary tract infections.

PURPOSE

To evaluate the therapeutic potential of P. capitata herba against gout by investigating its antihyperuricemia and antigouty arthritis effects and possible mechanisms.

METHODS

The ethanol extract (EP) and water extract (WP) of P. capitata herba were prepared by extracting dried and ground whole plants of P. capitata with 75% ethanol and water, respectively, followed by removal of solvents and characterization by UHPLC-Q-TOF/MS. The antihyperuricemia and antigouty arthritis effects of the two extracts were evaluated in a potassium oxonate- and hypoxanthine-induced hyperuricemia mouse model and a monosodium urate crystal (MSUC)-induced acute gouty arthritis mouse model, respectively. The mechanisms were investigated by testing their effects on the expression of correlated proteins (by Western blot) and mRNAs (by RT-PCR).

RESULTS

UHPLC-HRMS fingerprinting and two chemical markers (i.e., quercetin and quercitrin) determination were used for the characterization of the WP and EP extracts. Both WP and EP extracts showed pronounced antihyperuricemia activities, with a remarkable decline in serum uric acid and a marked increase in urine uric acid in hyperuricemic mice. Unlike the clinical xanthine oxidase (XOD) inhibitor allopurinol, WP and EP did not show any distinct renal toxicities. The underlying antihyperuricemia mechanism involves the inhibition of the activity and expression of XOD and the downregulation of the mRNA and protein expression of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1). The extracts of P. capitata herba also demonstrated remarkable anti-inflammatory activity in MSUC-induced acute gouty arthritis mice. The mechanism might involve inhibitory effects on the expression of proinflammatory factors.

CONCLUSIONS

The extracts of P. capitata herba possessed pronounced antihyperuricemia and antigouty arthritis effects and were, therefore, promising natural medicines for hyperuricemia-related disorders and gouty arthritis. The use of P. capitata herba for the treatment of urinary calculus may be, at least to some degree, related to its potential as an antihyperuricemia and antigouty arthritis drug.

Traditional Chinese Herbal Medicine Plays a Role in the Liver, Kidney, and Intestine to Ameliorate Hyperuricemia according to Experimental Studies

In the last few decades, hyperuricemia has drawn increasing attention owing to its global prevalence. Observational surveys have manifested that there is a relation between hyperuricemia and increased risks of hypertension, chronic kidney disease, cardiovascular events, metabolic disorders, end stage renal disease, and mortality. As alternatives, Traditional Chinese medicinal herbs have demonstrated concrete effects in mitigating hyperuricemia in different experiments. Researchers have made efforts to investigate the role of herbal medicine in attenuating hyperuricemia. This review focuses on traditional Chinese herbal medicines that have been reported to ameliorate hyperuricemia in experimental studies.

Saengmaeksan, a traditional herbal formulation consisting of Panax ginseng, ameliorates hyperuricemia by inhibiting xanthine oxidase activity and enhancing urate excretion in rats

Background

Saengmaeksan (SMS) is a traditional Korean medicine composed of three herbs, Panax ginseng, Schisandra chinensis, and Liriope platyphylla. SMS is used to treat respiratory and cardiovascular disorders. However, whether SMS exerts antihyperuricemic effects is unknown.

Methods

Effects of the SMS extract in water (SMS-W) and 30% ethanol (SMS-E) were studied in a rat model of potassium oxonate-induced hyperuricemia. Uric acid concentrations and xanthine oxidase (XO) activities were evaluated in the serum, urine, and hepatic tissue. Using renal histopathology to assess kidney function and uric acid excretion, we investigated serum creatinine and blood urea nitrogen concentrations, as well as protein levels of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), and organic anion transporter 1 (OAT1). The effects of SMS on in vitro XO activity and uric acid uptake were also evaluated. The components of SMS were identified using Ultra Performance Liquid Chromatography (UPLC).

Results

SMS-E reduced serum uric acid and creatinine concentrations, and elevated urine uric acid excretion. SMS-E lowered XO activities in both the serum and liver, and downregulated the expression of renal URAT1 and GLUT9 proteins. SMS-E reduced renal inflammation and IL-1β levels in both the serum and kidneys. SMS-E inhibited both in vitro XO activity and urate uptake in URAT1-expressing oocytes. Using UPLC, 25 ginsenosides were identified, all of which were present in higher levels in SMS-E than in SMS-W.

Conclusion

SMS-E exhibited antihyperuricemic effects by regulating XO activity and renal urate transporters, providing the first evidence of its applicability in the treatment of hyperuricemia and gout.

Recent Updates of Natural and Synthetic URAT1 Inhibitors and Novel Screening Methods

Human urate anion transporter 1 (hURAT1) is responsible for the reabsorption of uric acid in the proximal renal tubules and is a promising therapeutic target for treating hyperuricemia. To mitigate the side effects of URAT1-targeted clinical agents such as benzbromarone, there is significant interest in discovering new URAT1 inhibitors and developing technology that can evaluate URAT1 inhibition. This review summarizes the methods for assay of URAT1 inhibition and the progress on the discovery of natural and synthetic URAT1 inhibitors in the past five years.

A Head-To-Head Comparison of Benzbromarone and Allopurinol on the Risk of Type 2 Diabetes Mellitus in People With Asymptomatic Hyperuricemia

Objective: The study aimed to thoroughly address the influence of benzbromarone and allopurinol on the risk of the development of type 2 diabetes mellitus (T2DM) in people with asymptomatic hyperuricemia. Methods: We conducted a retrospective cohort study to examine the 2000-2015 national dataset containing all claims data of 23 million beneficiaries in Taiwan. Subjects who already had diabetes mellitus, gout-related diseases, and any cancer prior to the index date were excluded. Asymptomatic hyperuricemia was defined as subjects taking urate-lowering drugs who never had a gout flare. Subjects aged 20-84 with asymptomatic hyperuricemia who had benzbromarone prescriptions were selected as the benzbromarone group. Sex-matched and age-matched subjects with asymptomatic hyperuricemia who had allopurinol prescriptions were identified as the allopurinol group. The maximum follow-up duration was set as 5 years in our study. The outcome was set as subjects who had a new diagnosis of T2DM. The incidence density of T2DM was calculated in the benzbromarone and allopurinol groups. The hazard ratio (HR) and 95% confidence interval (CI) for T2DM was utilized to estimate the association between medications and the risk of T2DM. Results: The incidence of T2DM among benzbromarone users was significantly lower than that of allopurinol users (7.91 versus 8.48 per 100 person-years, incidence rate ratio = 0.93, and 95% CI = 0.87-0.99). After adjustment for co-variables, the adjusted HR of T2DM would be 0.91 (95% CI = 0.85-0.98 and p = 0.008) in benzbromarone users as compared to allopurinol users. Conclusion: There is a small but statistically significant risk reduction of developing T2DM in people with asymptomatic hyperuricemia taking benzbromarone as compared to those taking allopurinol during 5 years of follow-up. It indicates a future research direction for the use of individual urate-lowering drugs on the prevention of T2DM in the general population.

Enhanced Efficacy and Reduced Hepatotoxicity by Combination of Gnaphalium affine Extract and Benzbromarone in the Treatment of Rats with Hyperuricemic Nephropathy

Simultaneous oral intake of herbal medicine with chemical drugs may result in beneficial pharmacodynamic efficacy, including additive and synergistic effects with reduced toxicity. Gnaphalium affine D. Don (GAD) is a traditional Chinese Medicine that has been used for the management of hyperuricemia and gout. Benzbromarone (BBR) is one of the first-line drugs used for urate-lowering therapy in China but is toxic to the liver. The present study aimed to determine the effects of GAD and BBR, both alone and in co-treatment (with dosing interval of 1 hour), on chronic hyperuricemic nephropathy (HN) and hepatotoxicity in rats. Our data indicated that GAD significantly inhibited the elevation of serum uric acid, blood urea nitrogen, and creatinine levels in chronic HN rats at doses of 450 and 900 mg/kg/day. The rise in serum alanine aminotransferase and aspartate aminotransferase in BBR (or vehicle)-treated HN rats was significantly reduced by pre- (or post)-administration of GAD (450 mg/kg/day). The q-value >1.15 (by Jin method) indicated synergistic effects of co-treatments of BBR (50 mg/kg) with GAD (450 mg/kg). The synergistic beneficial effects were validated by comparison of BBR alone at a dose of clinical usage (4.5 mg/kg/day, in two divided doses) and BBR + GAD at half dose plus half dose (2.25 + 225 mg/kg/day) or half dose plus full dose (2.25 + 450 mg/kg/day). In conclusion, co-treatment with GAD and BBR holds promise for the management of hyperuricemia and gout.

Eggshell Membrane Ameliorates Hyperuricemia by Increasing Urate Excretion in Potassium Oxonate-Injected Rats

Hyperuricemia is the primary cause of gouty arthritis and other metabolic disorders. Eggshell membrane (EM) is an effective and safe supplement for curing pain and stiffness connected with osteoarthritis. However, the effect of EM on hyperuricemia is unclear. This study determines the effects of EM on potassium oxonate-injected hyperuricemia. Uric acid, creatinine, blood urea nitrogen concentrations in the serum, and xanthine oxidase activity in the liver are measured. Protein levels of renal urate transporter 1 (URAT1), organic anion transporters 1 (OAT1), glucose transporter 9 (GLUT9), and ATP-binding cassette transporter G2 (ABCG2) in the kidney are determined with renal histopathology. The results demonstrate that EM reduces serum uric acid levels and increases urine uric acid levels in hyperuricemic rats. Moreover, EM downregulates renal URAT1 protein expression, upregulates OAT1 and ABCG2, but does not change GLUT9 expression. Additionally, EM does not change xanthine oxidase activity in the liver or the serum. EM also decreases uric acid uptake into oocytes expressing hURAT1. Finally, EM markedly reduces renal inflammation and serum interleukin-1β levels. These findings suggest that EM exhibits antihyperuricemic effects by promoting renal urate excretion and regulating renal urate transporters. Therefore, EM may be useful in the prevention and treatment of gout and hyperuricemia.