esculetin and Hyperuricemia

Hyperuricemia (HUA) is a risk factor for chronic kidney disease (CKD). Serum uric acid (SUA) levels in CKD stage 3-4 patients closely correlate with hyperuricemic nephropathy (HN) morbidity. New uric acid (UA)-lowering strategies are required to prevent CKD. The multiple-purpose connectivity map (CMAP) was used to discover potential molecules against HUA and renal fibrosis. We used HUA and unilateral ureteral occlusion (UUO) model mice to verify renoprotective effects of molecules and explore related mechanisms. In vitro experiments were performed in HepG2 and NRK-52E cells induced by UA. Esculetin was the top scoring compound and lowered serum uric acid (SUA) levels with dual functions on UA excretion. Esculetin exerted these effects by inhibiting expression and activity of xanthine oxidase (XO) in liver, and modulating UA transporters in kidney. The mechanism by which esculetin suppressed XO was related to inhibiting the nuclear translocation of hexokinase 2 (HK2). Esculetin was anti-fibrotic in HUA and UUO mice through inhibiting TGF-β1-activated profibrotic signals. The renoprotection effects of esculetin in HUA mice were associated with lower SUA, alleviation of oxidative stress, and inhibition of fibrosis. Esculetin is a candidate urate-lowering drug with renoprotective activity and the ability to inhibit XO, promote excretion of UA, protect oxidative stress injury, and reduce renal fibrosis.

Topics: Animals; Cell Nucleus; Disease Models, Animal; Down-Regulation; Fibrosis; Hep G2 Cells; Humans; Hyperuricemia; Kidney; Male; Membrane Transport Proteins; Mice; Mice, Inbred ICR; NADPH Oxidases; NF-E2-Related Factor 2; Oxidative Stress; Protein Transport; Transcriptome; Umbelliferones; Ureteral Obstruction; Uric Acid; Xanthine Oxidase

Fraxini Cortex (also known as Qinpi, QP) has been used for the treatment of hyperuricemia with a significant difference on efficacy of QP from different regions. However, it`s still unknown whether proportion of components is the key and why same kind of herbs have different therapeutic effects. In this study, different sources of QP were collected from Shaanxi Qinpi extracts (SQPE), Henan Qinpi extracts (HQPE), Hebei Qinpi extracts (GQPE) provinces in China. Rat model of hyperuricemia with hypoxanthine combined with potassium oxonate were established to determine the levels of blood urea nitrogen (BUN), serum uric acid (SUA), urine uric acid (UUA) and creatinine (Cr). Hematoxylin-eosin staining (H&E) and Periodic Acid-Schiff staining (PAS) were performed for renal pathology while Western blot analysis and real-time PCR analysis for proteins and mRNA expression levels. High-performance liquid chromatograph (HPLC) was used for components and composition analysis. Our results demonstrated that QPE from different regions could alleviate hyperuricemia via increasing significantly the SCr and BUN levels whereas decreasing markedly UCr, SUA and UUA levels. Additionally, QPE could also improve the pathological changes of the kidneys. The protein and mRNA levels of urate reabsorption transporter 1 (URAT1) and glucose transporter 9 (GLUT9) were down-regulated by QPE treatment. SQPE hold a better activity on improving hyperuricemia and regulating URAT1 and GLUT9. HPLC analysis showed that the proportion of four components aesculin, aesculetin, fraxin, fraxetin were 9.002: 0.350: 8.980: 0.154 (SQPE); 0.526: 0.164: 7.938: 0.102 (HQPE); 12.022: 1.65: 0.878: 1.064 (GQPE). These data indicate that this proportion of effective components may be an important factor for efficacy of QP and had implications for the treatment of hyperuricemia.

Topics: Aesculus; Animals; Anion Transport Proteins; Biomarkers; Blood Urea Nitrogen; Coumarins; Creatinine; Disease Models, Animal; Dose-Response Relationship, Drug; Down-Regulation; Drugs, Chinese Herbal; Esculin; Gout Suppressants; Hyperuricemia; Kidney; Male; Monosaccharide Transport Proteins; Rats, Sprague-Dawley; Recovery of Function; Umbelliferones; Uric Acid