Comparing the Effects of Febuxostat and Allopurinol in an Animal Model of Metabolic Syndrome

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Reno-protective effects of xanthine oxidase inhibitors in patients with type 2 diabetes and chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

The effect of lowering uric acid levels on renal function in patients with diabetic kidney disease remains unclear. Previous randomized controlled trials (RCTs) have reported conflicting results regarding the effects of xanthine oxidase inhibitors on renal function. This study aimed to examine the renoprotective effects of xanthine oxidase inhibitors (febuxostat and topiroxostat) in patients with diabetic kidney disease.

METHODS

Relevant RCTs were searched using PubMed, Embase, and Cochrane Central databases. Ultimately, five RCTs were included in the meta-analysis. The assessed renal endpoints included changes in the estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio. The meta-analysis was conducted using Review Manager version 5.4. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for changes in renal endpoints between the groups after the study period. A subgroup analysis was conducted based on the type of intervention, results of the risk of bias assessment, and baseline renal function.

RESULTS

Although the use of febuxostat or topiroxostat did not induce a significant change in eGFR compared with the placebo, it showed a tendency to delay renal function decline (SMD = 0.32, 95% CI = [- 0.00; 0.64]). There was no significant difference in albuminuria between the two groups (SMD = 0.26, 95% CI = [- 0.10; 0.62]).

CONCLUSIONS

This study suggests the potential of febuxostat or topiroxostat to delay renal function decline in patients with diabetes and underlying renal impairment, that needs to be confirmed in further studies.

TRIAL REGISTRATION

INPLASY registration number 202450024.

Evaluation of Xanthine Oxidase Inhibitors Febuxostat and Allopurinol on Kidney Dysfunction and Histological Damage in Two-Kidney, One-Clip (2K1C) Rats

In chronic kidney disease (CKD), hyperuricemia is a common phenomenon, presumably due to reduced renal clearance of uric acid. This study investigated the effect of xanthine oxidase (XO) inhibitors allopurinol and febuxostat to prevent oxidative stress in the kidney of two-kidney, one-clip (2K1C) rats. In this investigation, 2K1C rats were used as an experimental animal model for kidney dysfunction. 2K1C rats were provided with food and drinking water and received febuxostat at a dose of 10 mg/kg or allopurinol at 100 mg/kg, respectively. After the treatment completion, all rats were sacrificed, and tissue samples were collected. 2K1C rats exhibited increased plasma creatinine, uric acid level, and glomerular injury assessed based on microscopic findings. Both allopurinol and febuxostat significantly normalized creatinine and uric acid levels. Furthermore, 2K1C rats showed increased lipid peroxidation (LPO), nitric oxide (NO), and advanced oxidation protein products (AOPP) alongside decreased superoxide dismutase (SOD) and catalase activity. Again, both drug treatments ameliorated these elevated oxidative stress parameters in 2K1C rats. The antioxidant genes such as Nrf-2, HO-1, and SOD were also restored in the kidneys of 2K1C rats by allopurinol and febuxostat treatment. 2K1C rats also showed increased IL-1β, IL-6, TNF-α, and NF-кB mRNA expression in the kidneys which were normalized by allopurinol and febuxostat treatment. Thus, the data suggest that XO inhibition protects kidney function potentially by restoring antioxidant enzyme function and suppressing inflammation.

Association Between Serum Uric Acid Levels and Metabolic-Associated Fatty Liver Disease in Southeast China: A Cross-Sectional Study

Objective

This study aimed to explore the association between serum uric acid (sUA) levels and metabolic-associated fatty liver disease (MAFLD) in Southeast China.

Methods

We performed a cross-sectional study of 2605 subjects who underwent physical examination between 2015 and 2017 in Southeast China. To explore the association between sUA levels and the risk of MAFLD, we employed logistic regression, restricted cubic spline (RCS), subgroups and multiplicative interaction analysis.

Results

Logistic regression analysis showed a positive association between sUA and MAFLD [aOR total population (95% CI)= 1.90 (1.49 ~ 2.42)], [aOR male (95% CI)= 2.01 (1.54 ~ 2.62)], [aOR female (95% CI)= 1.15 (0.62 ~ 2.11)], respectively. The RCS plot presented a significant nonlinear dose-response relationship between sUA levels and MAFLD risk, and the risk of MAFLD increased significantly when sUA> 5.56 mg/dL (P nonlinear< 0.001). Subgroups analysis revealed that the positive association between sUA and MAFLD was consistent across strata of gender, age, BMI, drinking status, smoking status and tea drinking status. Significant associations between sUA and MAFLD were not only found in males but also existed in subjects whose age ≤60, BMI ≥24 kg/m2, drinkers, smokers and tea-drinkers. Adjusted ORs were estimated to be 2.01, 1.95, 2.11, 2.29, 2.64 and 2.20, respectively. Multiplicative interactions were not observed between gender, age, drinking status, smoking status, tea drinking status and sUA (all P interaction> 0.05).

Conclusion

According to our study, sUA was positively associated with the risk of MAFLD. Additionally, the risk of MAFLD increased significantly when sUA levels exceeded 5.56 mg/dL. Our study may help clarify whether sUA plays a diagnostic role in MAFLD.

A Possible Therapeutic Application of the Selective Inhibitor of Urate Transporter 1, Dotinurad, for Metabolic Syndrome, Chronic Kidney Disease, and Cardiovascular Disease

The reabsorption of uric acid (UA) is mainly mediated by urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys. Dotinurad inhibits URAT1 but does not inhibit other UA transporters, such as GLUT9, ATP-binding cassette transporter G2 (ABCG2), and organic anion transporter 1/3 (OAT1/3). We found that dotinurad ameliorated the metabolic parameters and renal function in hyperuricemic patients. We consider the significance of the highly selective inhibition of URAT1 by dotinurad for metabolic syndrome, chronic kidney disease (CKD), and cardiovascular disease (CVD). The selective inhibition of URAT1 by dotinurad increases urinary UA in the proximal tubules, and this un-reabsorbed UA may compete with urinary glucose for GLUT9, reducing glucose reabsorption. The inhibition by dotinurad of UA entry via URAT1 into the liver and adipose tissues increased energy expenditure and decreased lipid synthesis and inflammation in rats. Such effects may improve metabolic parameters. CKD patients accumulate uremic toxins, including indoxyl sulfate (IS), in the body. ABCG2 regulates the renal and intestinal excretion of IS, which strongly affects CKD. OAT1/3 inhibitors suppress IS uptake into the kidneys, thereby increasing plasma IS, which produces oxidative stress and induces vascular endothelial dysfunction in CKD patients. The highly selective inhibition of URAT1 by dotinurad may be beneficial for metabolic syndrome, CKD, and CVD.

Celebrating Versatility: Febuxostat's Multifaceted Therapeutic Application

Febuxostat, initially developed as a xanthine oxidase inhibitor to address hyperuricemia in gout patients, has evolved into a versatile therapeutic agent with multifaceted applications. This review provides a comprehensive overview of febuxostat's mechanism of action, its effectiveness in gout management, its cardiovascular safety profile, renal and hepatic effects, musculoskeletal applications, safety considerations, and emerging research prospects. Febuxostat's primary mechanism involves selective inhibition of xanthine oxidase, resulting in reduced uric acid production. Its pharmacokinetics require personalized dosing strategies based on individual characteristics. In gout management, febuxostat offers a compelling alternative, effectively lowering uric acid levels, relieving symptoms, and supporting long-term control, especially for patients intolerant to allopurinol. Recent studies have demonstrated its cardiovascular safety, and it exhibits minimal hepatotoxicity, making it suitable for those with liver comorbidities. Febuxostat's potential nephroprotective effects and kidney stone prevention properties are noteworthy, particularly for gout patients with renal concerns. Beyond gout, its anti-inflammatory properties hint at applications in musculoskeletal conditions and a broader spectrum of clinical contexts, including metabolic syndrome. Emerging research explores febuxostat's roles in cardiovascular health, neurological disorders, rheumatoid arthritis, and cancer therapy, driven by its anti-inflammatory and antioxidative properties. Future directions include personalized medicine, combination therapies, mechanistic insights, and ongoing long-term safety monitoring, collectively illuminating the promising landscape of febuxostat's multifaceted therapeutic potential.

A New Avenue for Enhanced Treatment of Hyperuricemia and Oxidative Stress: Design, Synthesis and Biological Evaluation of Some Novel Mutual Prodrugs Involving Febuxostat Conjugated with Different Antioxidants

Febuxostat (FEB) is the first non-purine xanthine oxidase inhibitor (XOI) used for the treatment of hyperuricemia and gout. The oxidative stress induced by reactive oxygen species (ROS) which accompany purine metabolism by XO, could contribute to cellular damage and several pathological conditions. In this view, the present work addresses the evaluation of combining the hypouricemic effect of FEB and the free radical scavenging potential of various natural antioxidants in a single chemical entity by implementing the "mutual prodrug" strategy. Accordingly, a series of five ester prodrugs containing FEB together with different naturally occurring antioxidants namely, thioctic acid (4), thymol (5), menthol (6), vanillin (7), and guaiacol (8) was synthesized. Prominently, all the chemically conjugated prodrugs (4 - 8) revealed an obvious increase in the hypouricemic and antioxidant potentials when compared with their corresponding promoieties and physical mixtures. Moreover, they showed a potential protective effect against CCl4-induced hepatotoxicity and oxidative stress, together with no cytotoxicity on normal breast cells (MCF10A). Furthermore, the in vitro chemical and enzymatic stability studies of the prodrugs (4 - 8) using a developed HPLC method, verified their stability in different pHs, and rapid hydrolysis in rabbit plasma and liver homogenate to their parent metabolites. Moreover, the prodrugs (4 - 8) showed higher lipophilicity and lower aqueous solubility when compared to the parent drugs. Finally, the obtained merits from the implementation of the mutual prodrug strategy would encourage further application in the development of promising candidates with high therapeutic efficacy and improved safety profiles.

A feasible HPTLC method for concurrent quantitation of allopurinol-montelukast co-therapy in plasma and evaluation of their hepatic and renal effects in rats: Analytical, biochemical, and histopathological study

Recent studies presented the crucial role of montelukast (MON, a leukotriene receptor antagonist) against gouty arthritis and its protective effect on drug-induced liver and kidney injury. Allopurinol (ALO, a selective xanthine oxidase inhibitor) is also used for treatment of hyperuricemia, however, it induces hepatotoxicity and acute kidney injury. Therefore, this study introduces the first analytical/biochemical/histopathological assay for MON-ALO co-therapy and aims to: inspect the hepatic and renal impacts of ALO, MON and their combination in rats via biochemical and histopathological examinations, propose and validate a facile HPTLC method for concurrent estimation of ALO-MON binary mixture in human plasma, and employ this method to attain the targeted drugs in real rat plasma. First, the cited drugs in human plasma were simultaneously separated utilizing silica gel G 60 F₂₅₄-TLC plates. The separated bands were scanned at 268 nm demonstrating appropriate linearities (50.0-2000.0 ng band^-1 for each drug) and correlations (0.9986 and 0.9992 for ALO and MON, correspondingly). The calculated detection and quantitation limits, as well as recoveries confirmed the method's reliability. This procedure was validated, and the stability studies were achieved according to Bioanalytical Method Validation Guideline. This work was extended to investigate the possible hepatic and renal effects of ALO, MON and their co-therapy in rats. Using rat's gastric tube, the following was administered to four groups of male Wistar rats: Group Ia and Ib as control (received either saline or DMSO), Groups II, III, and IV were given MON, ALO, and MON+ALO, respectively. Good correlation between the measured biochemical parameters and the observed histopathological changes was encountered. Considerable drop in aspartate transaminase and alanine transaminase levels, in addition to lower liver damage changes were observed in the combination group compared to MON or ALO-treated groups. Regarding renal changes, ALO-MON co-therapy caused elevation in the serum creatinine and blood urea nitrogen levels when compared to controls and MON- or ALO-treated groups. Severe proteinaceous casts accumulation in kidney tubular lumen, severe congestion, and severe tubular necrosis were also noticed in the combination group. Lastly, this study suggests ALO-MON co-treatment not only as a preventive therapy against gouty arthritis but also as a new line to minimize ALO-induced hepatic injury. However, co-administration of ALO and MON should be further studied to assess the benefits and risks in various tissues, adjust the MON dosing, and monitor its nephrotoxic effect.

Allopurinol Use and the Risk of Type 2 Diabetes Mellitus: A Meta-Analysis of Cohort Studies

Objective

To assess whether there is a relation between allopurinol use and the probability of type 2 diabetes mellitus (T2DM) in persons with gout and/or hyperuricemia.

Methods

According to the PRISMA 2020 guidelines, a meta-analysis was performed by searching literature published from 2000 to 2021 in two electronic databases (Ebscohost and PubMed). The end point was set as a new diagnosis ofT2DM between people with the use of allopurinol and people with non-use of allopurinol. The random-effects model was performed to evaluate the pooled hazard ratio (HR) with 95% confidence interval (CI) for T2DM associated with allopurinol use.

Results

Three cohort studies could meet the inclusion criteria in the meta-analysis. There was a high heterogeneity of the outcome between studies (I² = 99%). The research duration ranged from 13 to 16 years. The subject number in each work ranged from 1114 to 138,652. A meta-analysis disclosed that there was not an association between allopurinol use and the risk of developing T2DM (pooled HR = 1.01 and 95%CI = .55–1.84).

Conclusions

The meta-analysis shows that no correlation is detected between allopurinol use and the risk of T2DM in individuals with gout and/or hyperuricemia. Because there are not enough eligible studies, the strength of evidence in our meta-analysis is weak. More cohort studies are needed to determine an association between use of allopurinol and the probability of T2DM for individuals with gout and/or hyperuricemia.