Clinical Effects of Topiroxostat on Renal and Endothelial Function in A Patient with Chronic Kidney Disease and Hyperuricemic Arteriolopathy: A Case Report

Optimal uric acid reduction to improve vascular endothelial function in patients with chronic heart failure complicated by hyperuricemia

Although an association of serum uric acid levels with endothelial function has been shown in various clinical settings, the optimal treatment target that would benefit vascular endothelial function has not been established. We, therefore, conducted a post hoc analysis of the Excited-UA study to identify an optimal target. Patients (N = 133) with chronic heart failure and comorbid hyperuricemia who enrolled in the Excited-UA study were divided into three tertiles based on their serum uric acid level 24 weeks after initiating xanthine oxidase inhibitor treatment with topiroxostat or allopurinol (i.e., groups with low, moderate, and high uric acid levels). Flow-mediated dilation (FMD) and reactive hyperemia index (RHI) values measured by reactive hyperemia peripheral arterial tonometry (RH-PAT) were compared among groups. The change from baseline in the FMD value 24 weeks after treatment was comparable among the three groups. In contrast, the change from baseline in the RHI was significantly different among the three groups (-0.153 ± 0.073, 0.141 ± 0.081 and -0.103 ± 0.104 in the low, moderate, and high uric acid level groups, respectively, P = 0.032). After adjustment for age, body mass index, and concomitant use of diuretics, which differed among the three groups, the change in the RHI in the moderate uric acid level group tended to be higher than that in the high uric acid level group (P = 0.057) and was significantly higher than that in the low uric acid level group (P = 0.020). These results indicate that targeting excessively low uric acid levels by treatment with xanthine oxidase inhibitors might be less beneficial for improving microvascular endothelial function in patients with chronic heart failure. Comparisons of the changes from baseline in vascular endothelial function parameters at 24 weeks among the 3 groups of low, moderae and high uric acid levels achieved with xanthine oxidase inhibitors. After adjustment for confounding factors, such as age, body mass index and concomitant diuretic use, which showed differences among the 3 groups, the change in RHI in the moderate uric acid level group tended to be higher than that in the high uric acid level group and was significantly higher than that in the low uric acid level group.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

Efficacy of Xanthine Oxidase Inhibitors in Lowering Serum Uric Acid in Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Objective: Current guidelines for gout recommend a treat-to-target approach with serum uric acid (SUA). However, there is little evidence for the dose-dependent effects of urate-lowering therapy (ULT). Herein, we analyzed the reported SUA-lowering effect and SUA target achievement differences for various doses of xanthine oxidase inhibitors. Methods: Approved ULT drugs were selected from the FDA Drug Database. We included prospective randomized controlled trials of ULT drugs from ClinicalTrials.gov, articles published in the journal “Drugs”, and Embase, a literature database. A meta-analysis was performed to determine the ability of different ULT drugs and doses to lower and maintain a target SUA < 6 mg/dL. Results: We identified 35 trials including 8172 patients with a baseline SUA of 8.92 mg/dL. The allopurinol, febuxostat, and topiroxostat showed dose-proportional SUA-lowering responses. Compared with allopurinol 300 mg daily, febuxostat 80 mg daily and 120 mg daily more effectively maintained SUA < 6 mg/dL. Conclusion: Allopurinol, febuxostat, and topiroxostat showed dose-proportional ability to lower and achieve a target SUA < 6 mg/dL. Significance and Innovations. We showed dose-dependent SUA lowering effects of allopurinol, febuxostat, and topiroxostat. Febuxostat is effective at ULT compared to allopurinol and could be potentially offered as an alternative agent when patients (1) have CKD, (2) have the human leukocyte antigen HLA-B*5801 allele, and (3) become refractory to allopurinol. Gradual allopurinol dose increase with a lower starting dose is needed in CKD.

Green tea polyphenols protect against preglomerular arteriopathy via the jagged1/notch1 pathway

Preglomerular arteriopathy (PA) induced by hyperuricemia contributes to the progression of chronic kidney disease (CKD). Green tea polyphenols (GTPs) are antioxidant ingredients thought to assist in preventing hyperuricemia. However, the underlying mechanism by which GTPs affect renal function remains unclear. Both normal and remnant kidney (RK) rats were administrated oxonic acid (OX) to induce hyperuricemia. The hyperuricemia RK rats were concomitantly treated with GTPs. Hematoxlyin-eosin (H&E) and periodic acid-Schiff (PAS) staining methods were used to examine renal function and arterial morphology. The expression of proteins in the Jagged1/Notch1 pathway was assessed via immunohistochemistry, in situ hybridization, the quantitative polymerase chain reaction (qPCR), and western blotting techniques. Our results showed that an RK rat model with preglomerular vascular disease had been successfully established. Treatment of the RK rats with GTPs effectively alleviated the damage due to preglomerular arteriopathy, significantly alleviated pathological symptoms, and reduced the levels of proteinuria, serum UA, BUN, and creatinine. Our results also suggested involvement of the Jagged1/Notch1 pathway in the preglomerular vascular lesions. The levels of Jagged1, Notch1-ICD, Hes5, and p-STAT3 were significantly decreased in RK + OA-treated rats when compared with those in RK rats. Treatment with GTPs upregulated the levels of Jagged1, Notch1, Hes5, p-STAT3, and MnSOD2, and downregulated xanthine oxidase (XO) expression in rats with preglomerular arteriopathy. However, the beneficial effects of GTPs were lost when the Jagged1/Notch1-STAT3 pathway was inactivated by siRNA. In conclusion, GTPs exert a therapeutic effect on perglomerular arteriopathy. Our results also revealed a novel mechanism that mediates preglomerular arteriopathy, and suggest GTPs as effective novel renal protective agents.