Hyperuricemia research progress in model construction and traditional Chinese medicine interventions

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

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

α-Amyrin and β-Amyrin Isolated from Celastrus hindsii Leaves and Their Antioxidant, Anti-Xanthine Oxidase, and Anti-Tyrosinase Potentials

Celastrus hindsii is a popular medicinal plant in Vietnam and Southeast Asian countries as well as in South America. In this study, an amount of 12.05 g of an α-amyrin and β-amyrin mixture was isolated from C. hindsii (10.75 g/kg dry weight) by column chromatography applying different solvent systems to obtain maximum efficiency. α-Amyrin and β-amyrin were then confirmed by gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR). The antioxidant activities of the α-amyrin and β-amyrin mixture were determined via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays with IC₅₀ of 125.55 and 155.28 µg/mL, respectively. The mixture exhibited a high potential for preventing gout by inhibiting a relevant key enzyme, xanthine oxidase (XO) (IC₅₀ = 258.22 µg/mL). Additionally, an important enzyme in skin hyperpigmentation, tyrosinase, was suppressed by the α-amyrin and β-amyrin mixture (IC₅₀ = 178.85 µg/mL). This study showed that C. hindsii is an abundant source for the isolation of α-amyrin and β-amyrin. Furthermore, this was the first study indicating that α-amyrin and β-amyrin mixture are promising in future therapies for gout and skin hyperpigmentation.

Standardization of Diploid Codonopsis laceolata Root Extract as an Anti-Hyperuricemic Source

Codonopsis lanceolate exerts various medicinal effects and has been used as a traditional medicine for inflammation, asthma, gastritis, and liver disease. Recently, we reported the xanthine oxidase inhibitory activity of C. lanceolata extract and that lobetyolin, one of the key components, was a xanthine oxidase inhibitor. Lobetyolin showed anti-hyperuricemic activity in vitro and in vivo. In this study, we prepared various types of C. lanceolata extracts for the development of functional materials and natural drugs. We present the optimal analytical approach for the quality control and extraction optimization of C. lanceolata preparations. We established and validated a HPLC analysis for easy separation and quantification of the lobetyolin biomarker. Solvent extracts of C. lanceolata root were prepared and the profiles of the active marker and the optimal extraction methods were evaluated. The 100% ethanolic extract demonstrated the highest lobetyolin content. The validated HPLC method confirmed that lobetyolin was present in C. lanceolata root extracts. We suggest that the anti-hyperuricemic activities of C. lanceolata extract could be attributed to this marker compound. The results proposed that the 100% ethanolic extract could be used for the prevention of hyperurecemia, and that this analytical method and biomarker could be useful for the quality control of C. lanceolata preparations.

Comparison of the Effects of Allopurinol and Febuxostat on the Values of Triglycerides in Hyperuricemic Patients

Introduction:

Hyperuricemia is an independent risk factor for the development of many diseases.

Aim:

The aim of this paper is to compare the effects of allopurinol and febuxostat on the values of triglycerides and uric acid in hyperuricemic patients.

Methods:

This was a pharmacological-clinical retrospective-prospective study. The research sample comprised 50 examinees of both genders and different ages who were undergoing allopurinol (100 mg/day) or febuxostat (80 mg/day) therapy. Statistical Product and Service Solutions (SPSS) Software and Microsoft Excel were used for statistical analysis.

Results:

Examinees who were treated with allopurinol had a statistically significant decrease in uric acid concentrations (by 126.28 ± 20.36 μmol/l) at the end of the observation compared to the initial values (p = 0.006). Examinees who were treated with febuxostat had a statistically significant decrease in uric acid concentrations (by 252.80 ± 94.17 μmol/l) at the end of the observation compared to the initial values (p = 0.001). The initial value of triglycerides was 1.58 ± 0.64 mmol/l in allopurinol-treated examinees, and 1.60 ± 0.52 mmol/l in febuxostat-treated examinees. After three and six months of allopurinol use, there was a statistically significant increase in triglyceride values (p = 0.046 and p = 0.042, respectively). A statistically significant decrease in triglyceride values (by 0.16 ± 0.10 mmol/l) was noted after three months of febuxostat use (p = 0.012).

Conclusion:

The results of this research confirmed the previous findings and pointed out the positive pharmacological effects of allopurinol and febuxostat.

Febuxostat is superior to allopurinol in delaying the progression of renal impairment in patients with chronic kidney disease and hyperuricemia

PURPOSE

This study aimed to compare efficacy of renal-protective function between febuxostat and allopurinol in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).

METHODS

Totally 152 CKD stage 2-3 patients complicated with HUA were recruited. According to their uric acid-lowering therapy, there were 67 patients included in febuxostat group and 85 in allopurinol group, respectively. Estimated glomerular filtration rate (eGFR), serum creatinine (Scr), 24-h proteinuria, serum uric acid (SUA) were measured at M0, M1, M3 and M6 after the treatment. Primary outcome was proportion of patients showing ≥ 10% decline in eGFR from baseline at M6.

RESULTS

The eGFR at M6 was numerically higher at M6 and eGFR change (M6-M0) was increased in febuxostat group compared with allopurinol group. Most importantly, the proportion of patients showing a ≥ 10% decline in eGFR from baseline at M6 was reduced in febuxostat group compared with allopurinol group. Multivariate logistic regression analyses further validated that febuxostat vs. allopurinol was an independent predictor for reduced risk of eGFR decline ≥ 10% from baseline. Besides, SUA change (M6-M0) was decreased, but Scr change (M6-M0) and 24-h proteinuria change (M6-M0) were similar in febuxostat group compared with allopurinol group.

CONCLUSIONS

Febuxostat presents a superior effect in delaying renal impairment progression compared with allopurinol in CKD patients complicated with HUA.

Effects of lobetyolin on xanthine oxidase activity in vitro and in vivo: weak and mixed inhibition

Lobetyolin (LBT), a general marker compound mainly found in Codonopsis plants including C. pilosula, C. tubulosa, and C. lanceolata, exhibits antitumor, antiviral, anti-inflammatory, mucosal protective, and antioxidant activities. Xanthine oxidase (XO) catalyzes the formation of uric acid from xanthine, a critical metabolic pathway related to hyperuricemia and gout. The aim of this study was to investigate the effect of LBT on XO activity and its mechanism using in vitro enzyme assay system and in vivo potassium oxonate-induced hyperuricemic mice. LBT was found to weakly inhibit XO activity via a mixed type mechanism. Consistently, the impact of 1-week oral LBT treatment on serum XO activity in vivo is limited in hyperuricemic mice. However, oral LBT at 50 mg/kg significantly reduced hepatic XO activity in vivo. To the best of our knowledge, this is the first study to report effects of LBT on XO activity and its inhibition mechanism.

Febuxostat inhibits TGF‑β1‑induced epithelial‑mesenchymal transition via downregulation of USAG‑1 expression in Madin‑Darby canine kidney cells in vitro

Our previous study demonstrated that febuxostat, a xanthine oxidase inhibitor, can alleviate kidney dysfunction and ameliorate renal tubulointerstitial fibrosis in a rat unilateral ureteral obstruction (UUO) model; however, the underlying mechanisms remain unknown. Increasing evidence has revealed that epithelial-mesenchymal transition (EMT) is one of the key mechanisms mediating the progression of renal tubulointerstitial fibrosis in chronic kidney disease (CKD). Uterine sensitization-associated gene-1 (USAG-1), a kidney-specific bone morphogenetic protein antagonist, is involved in the development of numerous types of CKDs. The present study aimed to investigate the role of febuxostat in the process of EMT in Madin-Darby canine kidney (MDCK) cells in vitro. Western blotting, reverse transcription-semiquantitative polymerase chain reaction analysis and immunofluorescence staining were used to evaluate the expression levels of bone morphogenetic protein 7, USAG-1, α-smooth muscle actin (α-SMA) and E-cadherin, respectively. The results demonstrated that the expression of USAG-1 and α-SMA increased, and that of E-cadherin decreased significantly in MDCK cells following treatment with transforming growth factor-β1 (TGF-β1). The application of small interfering RNA-USAG-1 potently inhibited TGF-β1-induced EMT. Subsequently, the effects of febuxostat on TGF-β1-induced EMT was investigated. The results demonstrated that febuxostat downregulated the expression of USAG-1, and reversed TGF-β1-induced EMT in MDCK cells. Furthermore, pretreatment with febuxostat significantly restored the decreased expression levels of phosphorylated Smad1/5/8 induced by TGF-β1 in MDCK cells. The results of the present study suggested that USAG-1 may be involved in the EMT process of MDCK cells induced by TGF-β1, and febuxostat inhibited EMT by activating the Smad1/5/8 signaling pathway via downregulating the expression of USAG-1 in MDCK cells.

Managing Gout in the Patient with Renal Impairment

Hyperuricaemia is an independent risk factor for renal function decline. Evidence is emerging that urate-lowering therapy might be beneficial in subjects with renal impairment. We  review the association between renal impairment and gout, some of the related pathogenic processes and the possible impact of gout treatment on the progression of renal impairment. Nevertheless, the management of gout is more complex in the presence of chronic kidney disease. The main aim of gout therapy is to fully dissolve the urate crystals, thus curing the disease. Avoidance of attacks-prophylaxis-and their prompt treatment if they occur, along with accurate information to patients, completes the treatment strategy. This article provides a practical guide to managing gout in older patients and in those with renal impairment. We highlight the shortcomings in our current treatment options and strategies.

Efficacy and safety of febuxostat for treating hyperuricemia in patients with chronic kidney disease and in renal transplant recipients: A systematic review and meta-analysis

Febuxostat is potent and well-tolerated in the management of chronic gout. However, its clinical efficacy and safety in the treatment of hyperuricemia in patients with chronic kidney disease (CKD) and in renal transplant recipients have remained to be fully determined. The MEDLINE, EMBASE and Cochrane Library databases were searched for relevant articles. Data were extracted and pooled results were estimated from the standard mean difference (SMD) with 95% confidence intervals (95% CIs). The quality of the studies included was assessed, and their publication bias was examined. Four prospective randomized controlled trials and two retrospective observational studies were included in the systematic review and meta-analysis. Febuxostat administration significantly reduced the serum uric acid concentration in patients with CKD and in renal transplant recipients when compared with allopurinol or placebo in the short-term (1 month: SMD, −2.24; 95% CI, −3.59 to −0.89; P-value of SMD=0.001; I², 92.4%; 3 months: SMD, −1.20; 95% CI, −2.04 to −0.36; P-value of SMD=0.005; I², 88.9%; 6 months: SMD, −1.49; 95% CI, −2.68 to −0.30; P-value of SMD=0.014; I², 92.9%). Furthermore, the increase in the estimated glomerular filtration rate in the febuxostat group was significantly higher than that in the control group (SMD, 0.30; 95% CI, 0.031 to 0.58; P-value of SMD=0.029; I², 0.0%). No significant difference in the changes in serum creatinine (Scr), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) was identified between the two groups (Scr: SMD, −0.17; 95% CI, −0.97 to 0.63; P-value of SMD=0.67; I², 79.2%; LDL: SMD, −0.21; 95% CI, −0.49 to 0.07; P-value of SMD=0.13; I², 34.1%; HDL: SMD, −0.05; 95% CI, −0.70 to 0.61; P-value of SMD=0.89; I², 69.2%). In conclusion, febuxostat is a potent and well-tolerated agent for the short-term management of hyperuricemia in patients with CKD and in renal transplant recipients. However, these data should be interpreted with caution due to the varied design of the studies included in the present meta-analysis.

Identification of new drug-like compounds from millets as Xanthine oxidoreductase inhibitors for treatment of Hyperuricemia: A molecular docking and simulation study

Xanthine oxidoreductase plays an important role in formation of uric acid and its regulation during purine catabolism. Uncontrolled expression of this enzyme is responsible for overproduction and deposition of uric acid in blood that is potentially injurious because it can breakdown DNA and protein molecules, triggering many diseases. Human Xanthine oxidoreductase (HsXOR) is considered to be a pharmacological target for the treatment of hyperuricemia. Many of the HsXOR-inhibitor drugs such as Febuxostat and Allopurinol are known to have significant adverse effects. Therefore, there is an urgent need to develop new HsXOR-inhibitor drugs with less or no toxicity for the long-term treatment or prevention of hyperuricemia-related diseases. Many nutritious and medical functions have been reported in millets. Present work deals with identification of millet derived compounds in terms of their interaction with target, HsXOR through molecular docking and dynamic simulation studies. Of thirty two chosen compounds, Luteolin and Quercitin showed more binding affinity with HsXOR than reference drugs, Febuxostat and Allopurinol. Molecular dynamics simulations (20 ns long) revealed that Luteolin-protein complex was energetically more stable than Quercitin-protein complex. The millet derived compounds i.e. Luteolin and Quercitin showed binding energy -9.7 kcal/mol whereas the known drugs i.e. Febuxostat and Allopurinol showed binding energy -8.0 kcal/mol and -5.5 kcal/mol respectively. Based on the study, Luteolin possess high potential to be considered for trial as an inhibitor of HsXOR as it may regulate the pathway by inhibiting HsXOR. Further investigations are proposed to consider Luteolin for developing future drugs from millets and other natural sources.

Innovative HPTLC method with fluorescence detection for assessment of febuxostat–montelukast combination and study of their protective effects against gouty arthritis

This study was designed to evaluate the potential protective effects of montelukast, febuxostat and their combination on a model of acute gouty arthritis, and to establish a HPTLC method for determination of both drugs simultaneously.

Risk of Febuxostat-Associated Myopathy in Patients with CKD

BACKGROUND AND OBJECTIVES

Febuxostat, a nonpurine xanthine oxidase inhibitor, is widely used to treat hyperuricemia. Although febuxostat-associated rhabdomyolysis was reported in some patients with CKD, the association between CKD and febuxostat-associated myopathy remains uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our retrospective cohort study included 1332 patients using febuxostat in Taipei Medical University-Wanfang Hospital from February of 2014 to January of 2016. The primary predictor was time-averaged eGFR as calculated by the equation proposed by the 2009 Chronic Kidney Disease Epidemiology Collaboration. The outcome was febuxostat-associated myopathy defined as elevated creatine kinase levels during febuxostat use that were not attributed to other muscular injuries.

RESULTS

The median duration of febuxostat use was 224 days (25th, 75th percentiles: 86, 441.5 days). Of 1332 study participants, 1222 (91.7%) had CKD; the median eGFR was 20.8 ml/min per 1.73 m2 (25th, 75th percentiles: 9.0, 35.4 ml/min per 1.73 m2). Forty-one of the participants had febuxostat-associated myopathy (3.2%). All patients with myopathy had CKD, and the incident rate was 0.013 (95% confidence interval, 0.01 to 0.02) events per 100 patient-days in patients with CKD. Of 41 patients with myopathy, 37 had myositis, and four had rhabdomyolysis. Myopathy resolved in 17 patients who withdrew from treatment and eight patients who continued febuxostat treatment. Among the evaluated predictors, multivariate analysis showed that only the lowest eGFR tertile was significantly associated with myopathy in febuxostat users. The odds ratio of the lowest eGFR tertile to the highest tertile was 4.21 (95% confidence interval, 1.7 to 10.43). This finding remained consistent among subgroups stratified by age, sex, diabetes status, coronary artery disease, and statin or fibrate use.

CONCLUSIONS

Patients with severely reduced eGFR had higher risk of myopathy with treatment of febuxostat. Regular monitoring of creatine kinase level is suggested for early detection of febuxostat-associated myopathy, particularly in patients with CKD.