Expression of renal Oat5 and NaDC1 transporters in rats with acute biliary obstruction

AIM: To examine renal expression of organic anion transporter 5(Oat5) and sodium-dicarboxylate cotransporter 1(Na DC1), and excretion of citrate in rats with acute extrahepatic cholestasis.METHODS: Obstructive jaundice was induced in rats by double ligation and division of the common bile duct(BDL group). Controls underwent sham operation that consisted of exposure, but not ligation, of the common bile duct(Sham group). Studies were performed 21 h after surgery. During this period, animals were maintained in metabolic cages in order to collect urine. The urinary volume was determined by gravimetry. The day of the experiment, blood samples were withdrawn and used to measure total and direct bilirubin as indicative parameters of hepatic function. Serum and urine samples were used for biochemical determinations. Immunoblotting for Oat5 and Na DC1 were performed in renal homogenates and brush border membranes from Sham and BDL rats. Immunohistochemistry studies were performed in kidneys from both experimental groups. Total RNA was extracted from rat renal tissue in order to perform reverse transcription polymerase chain reaction. Another set of experimental animals were used toevaluate medullar renal blood flow(m RBF) using fluorescent microspheres.RESULTS: Total and direct bilirubin levels were significantly higher in BDL animals, attesting to the adequacy of biliary obstruction. An important increase in m RBF was determined in BDL group(Sham: 0.53 ± 0.12 m L/min per 100 g body weight vs BDL: 1.58 ± 0.24 m L/min per 100 g body weight, P < 0.05). An increase in the urinary volume was observed in BDL animals. An important decrease in urinary levels of citrate was seen in BDL group. Besides, a decrease in urinary citrate excretion(Sham: 0.53 ± 0.11 g/g creatinine vs BDL: 0.07 ± 0.02 g/g creatinine, P < 0.05) and an increase in urinary excretion of H+(Sham: 0.082 ± 0.03 μmol/g creatinine vs BDL: 0.21 ± 0.04 μmol/g creatinine, P < 0.05) were observed in BDL animals. We found upregulations of both proteins Oat5 and Na DC1 in brush border membranes where they are functional. Immunohistochemistry technique corroborated these results for both proteins. No modifications were observed in Oat5 m RNA and in Na DC1 m RNA levels in kidney from BDL group as compared with Sham ones.CONCLUSION: Citrate excretion is decreased in BDL rats, at least in part, because of the higher Na DC1 expression. Using the outward gradient of citrate generated by Na DC1, Oat5 can reabsorb/eliminate different organic anions of pathophysiological importance.

Urea transporter inhibitors identified as novel diuretics

Urea transporters （UT）, including isoforms of UT-A endothelia and erythrocytes, play an important role in the urine in kidney tubule epithelia and UT-B in vasa recta concentration mechanism by mediated an intrarenalurea recycling, suggesting that functional inhibition of these proteins could have therapeutic use as diuretic. By in- tegrated cell based high throughput screening and in silico methods, a class of small-molecule drug-like compounds with thienoquinolin core structure was found to have inhibition activity on both UT-A and UT-B. The structure and activity relationship analysis showed a compound PU-48, named chemically as methyl 3-amino-6-methoxythieno[ 2, 3-b] quinoline-2-carboxylate, had the best UT-A and UT-B inhibition activity. IC50s of PU-48 on UT-B facilitated as determined by erythrocyte lysis assay. In vivo urea transport were micromole level in human, rat, and mouse, activity of PU-48 on urinary concentrating function was evaluated in rats fed ad libitum in metabolic cages. Urine output significantly increased in a dose-dependent manner in rats subcutaneously administered PU-48. Urinary os- molality and urea concentration were significantly decreased. The peak changes of urine output, urinary osmolality and urinary urea concentration occurred between 2 and 4 h after PU/18 administration, with values returning to was subcutaneously injected every 6 h the 24 h urine output in baseline by 10 h. When PU-48 at 50 mg · kg^-1 PU-48 treated rats was significantly higher than that in vehicle control rats. Urinary osmolality and urea concentra- tion in PU-48 treated rats were significantly lower than in vehicle control rats. The excretion of Na ＋ , K ＋ , C1- was PU-48 treated rats had significantly higher urea excre- similar in PU-48 treated and vehicle control rats. However, tion than vehicle control rats. The data suggest that PU-48 caused a urea-selective diuresis without disturbing elec- TGs, and LDL-C in PU-48-treated rats were similar with those trolyte metabolism. Notably, blood urea, T-CHO, in vehicle control rats, which are normal levels. These data indicate that the diuretic effect of PU-14 does not cause electrolyte imbalance and abnormal metabolism. It is predicated that UT inhibitors have potential clinical applica- tions as sodium-sparing diuretics in edema from different etiologies, such as congestive heart failure and cirrhosis.

Influence of organic anion transporting potypeptide(SLCO1B1 and SLCO1B3)genetic polymorphisms on mycophenolic acid in Chinese kidney transplantation patients

Objective To analyze the relationship between genetic polymorphisms of organic anion transporting polypeptide ( SLCO1B1 and SLCO1B3) and mycophenolic acid ( MPA) pharmacokinetics in Chinese kidney transplant recipients. Methods Gene mutations ( SLCO1B3 T334G,SLCO1B1 A338G) were detected in 68 recipi-

LifePort保存心脏死亡器官捐献供肾在肾移植中的应用

目的研究肾脏转运器(LifePort)保存心脏死亡后器官捐献者供肾在肾移植中的应用,为患者的恢复提供临床指导。方法回顾性分析深圳市第三人民医院泌尿外科2017年7月至2019年2月期间接诊的25例心脏死亡器官捐献(DCD)供肾移植后受者的临床资料,根据同一供体两只供肾LifePort保存和普通冷藏两种不同的保存方式,将其分为研究组和对照组,各25例。检测并记录两组受者术后15 d可溶性细胞间黏附分子1(sICAM-1)、超氧化物歧化酶(SOD)、丙二醛(MDA)血清含量、术后移植物功能恢复延迟(DGF)、肾功能恢复时间及住院时间、术后并发症发生率、术后1年肾生存率和受者生存率。结果研究组患者术后DGF发生率为8.0%,明显低于对照组的32.0%,差异有统计学意义(P<0.05);研究组患者术后1年肾生存率和受者生存率均为100.0%,分别与对照组的96.0%和100.0%比较差异均无统计学意义(P>0.05);研究组患者肾功能恢复时间和住院时间分别为(12.5±3.3)d和(18.3±5.8)d,明显短于对照组的(15.6±4.7)d和(22.1±6.4)d,差异均具有统计学意义(P<0.05);研究组患者的sICAM-1和MDA血清含量分别为(318.4±47.3)μg/L和(2.8±0.4)μg/L,明显低于对照组的(531.5±68.9)μg/L和(3.4±0.5)μg/L,SOD活性峰值为(81.3±5.7)IU/mL,明显高于对照组的(72.5±4.3)IU/mL,差异均有统计学意义(P<0.05);研究组患者并发症总发生率为12.0%,略低于对照组的20.0%,但差异无统计学意义(P>0.05)。结论LifePort有利于改善心脏死亡后器官捐献供者供肾的保存质量,降低受者术后DGF发生率,有利于促进移植肾功能恢复,缩短受者住院时间,且对术后并发症发生率和受者生存率不会产生任何影响,具有临床应用价值。

New insights into renal lipid dysmetabolism in diabetic kidney disease

Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs,including the kidney.Research suggests that impaired cholesterol metabolism,increased lipid uptake or synthesis,increased fatty acid oxidation,lipid droplet accumulation and an imbalance in biologically active sphingolipids(such as ceramide,ceramide-1-phosphate and sphingosine-1-phosphate)contribute to the development of diabetic kidney disease(DKD).Currently,the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production,oxidative stress,inflammation,or cell death.Therefore,control of renal lipid dysmetabolism is a very important therapeutic goal,which needs to be archived.This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.

Single Nucleotide Polymorphisms (SNPs) of URAT1 (rs7932775) and ABCG2 (rs3825016) on Chronic Kidney Disease Patients with Hyperuricemia

Background: More and more chronic kidney disease (CKD) patients are accompanied with hyperuricaemia. As is known, hyperuricaemia is an independent hazard of both cardiovascular diseases (CVD) and chronic kidney diseases. We aim at identifying Single Nucleotide Polymorphism (SNP) difference of hURAT1 (rs7932775) and ABCG2 (rs3825016) on CKD patient with hyperuricemia and/or gout. Methods: All forty-two CKD patients were divided into two groups: hyperuricemia, and control group. 24 hours urine sample and serum were prepared for testing biochemistry parameters. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method is used to analyze hURAT1 and ABCG2 single nucleotide polymorphisms in different groups. Results: 17 patients have CT SNP of hURAT1 (rs7932775) and 13 patients have CT SNP of ABCG2 (rs3825016) in hyperuricemia group, while only 5 persons and 6 persons have the same mutations in control group respectively. 7 patients have CT SNP of both hURAT1 (rs7932775) and ABCG2 (rs3825016) in hyperuricemia group, while only 2 persons have the same mutations in control group. CT mutation rates of hURAT1 (rs7932775) and ABCG2 (rs3825016) in hyperuricemia group were 60.7% (17/28) and 50% (13/28) respectively, higher than that of control group (35.7% (5/14) and 42.8% (6/14)). What is more, Double SNP mutations in both hURAT1 (rs7932775) and ABCG2 (rs3825016) in hyperuricemia group were 25% (7/28), higher than that of control group (14.2%, 2/14). Conclusion: There are higher mutation rates of CT SNP in hURAT1 (rs7932775) and/or ABCG2 (rs3825016) in hyperuricemia group. We can conclude that hyperuricemia is a high risk factor in progress of CKD, which is necessary to take measures of decreasing serum uric acid to delay CKD progress.

Effects of Citrullus colocynthis Seed Aqueous Extracts upon Sodium Transport across A6 Kidney Cell Monolayers

Background:Various extracts from Citrullus colocynthis seeds were recently examined for their possible favorable effects on glucose homeostasis,other metabolic variables,and pancreatic islet size in streptozotocin-induced diabetic rats.Objective:Considering the effectiveness of insulin upon target cells as another process susceptible to be influenced by plant extracts,the present study is used to compare the effects of either crude or defatted aqueous extracts from C.colocynthis seeds upon Na+transport in A6 kidney cells.Method:The intensity of electrical currents,taken as the potential difference divided by the epithelial resistance was measured in monolayers of A6 kidney cells exposed at the basolateral side to either crude untreated aqueous(EI)or defatted aqueous(EII)extracts,as well as their fractions EI1 and EII1 containing components with high molecular weight(>5 kDa),and EI2 and EII2 containing components with low molecular weight(<5 kDa).The effect of insulin was to assess the functional integrity of the A6 monolayer.Results:All extracts caused a rapid and sustained increase in current intensity.The defatted aqueous extract(EII)was more efficient than the non-defatted aqueous extract(EI)in terms of increasing the intensity of current in the A6 monolayer.The components of the defatted aqueous extract responsible for such a greater efficiency were located in the fraction containing components with low molecular weight and acted in a time-related progressive fashion upon Na+transport.Conclusion:These data suggest that colocynth seed extracts mainly containing components with low molecular weight increased the current intensity in A6 cells,thus suggesting that colocynth may affect Na+transport in kidney cells.

Empagliflozin alleviates podocytopathy and enhances glomerular nephrin expression in db/db diabetic mice

BACKGROUND Modern guidelines recommend sodium-glucose cotransporter-2(SGLT2)inhibitors as the preferred antihyperglycemic agents for patients with type 2 diabetes and chronic kidney disease.However,the mechanisms underlying the renal protective effect of SGLT2 inhibitors are not fully understood.structure of podocytes and nephrin expression in glomeruli in db/db diabetic mice.METHODS We treated 8-wk-old male db/db mice with EMPA(10 mg/kg/d)or vehicle for 8 wk.Age-matched male db/+mice were included as non-diabetic controls.Parameters of body composition,glycemic and lipid control,and plasma concentrations of leptin,insulin and glucagon were assessed.We evaluated renal hypertrophy as kidney weight adjusted to lean mass,renal function as plasma levels of creatinine,and albuminuria as the urinary albumin-to-creatinine ratio(UACR).Renal structures were studied by light and transmission electron microscopy with a focus on mesangial volume and podocyte structure,respectively.Glomerular nephrin and transforming growth factor beta(TGF-β)were assessed by immunohistochemistry.RESULTS Severe obesity and hyperglycemia developed in db/db mice prior to the start of the experiment;increased plasma concentrations of fructosamine,glycated albumin,cholesterol,leptin,and insulin,and elevated UACR were detected.Mesangial expansion,glomerular basement membrane thickening,and increased area of TGF-βstaining in glomeruli were revealed in vehicle-treated mice.Podocytopathy was manifested by effacement of foot processes;nephrin-positive areas in glomeruli were reduced.EMPA decreased the levels of glucose,fructosamine and glycated albumin,UACR,kidney hypertrophy,mesangial expansion,glomerular basement membrane thickening,and glomerular TGF-βstaining,alleviated podocytopathy and restored glomerular staining of nephrin.CONCLUSION These data indicate that EMPA attenuates podocytopathy in experimental diabetic kidney disease.The anti-albuminuric effect of EMPA could be attributed to mitigation of podocyte injury and enhancement of nephrin expression.

Siwu decoction attenuates oxonate-induced hyperuricemia and kidney inflammation in mice

The aim of the study was to investigate the effects of Siwu decoction on hyperuricemia, kidney inflammation, and dysfunction in hyperuricemic mice. Siwu decoction at 363.8, 727.5, and 1 455 mg·kg^(–1) was orally administered to potassium oxonate-induced hyperuricemic mice for 7 days. Serum urate, creatinine, and blood urea nitrogen levels and hepatic xanthine oxidase(XOD) activity were measured. The protein levels of hepatic XOD and renal urate transporter 1(URAT1), glucose transporter 9(GLUT9), organic anion transporters 1(OAT1), ATP-binding cassette subfamily G member 2(ABCG2), organic cation transporter 1(OCT1), OCT2, organic cation/carnitine transporter 1(OCTN1), OCNT2, Nod-like receptor family, pyrin domain containing 3(NLRP3), apoptosis-associated speck-like protein(ASC), Caspase-1, and interleukin-1β(IL-1β) were determined by Western blotting. Renal histopathology change was obtained following hematoxylin-eosin staining. Our results indicated that Siwu decoction significantly reduced serum urate, creatinine and blood urea nitrogen levels and increased fractional excretion of uric acid in hyperuricemic mice. It effectively reduced hepatic XOD activity and protein levels in this animal model. Furthermore, Siwu decoction down-regulated URAT1 and GLUT9 protein levels, and up-regulated the protein levels of OAT1, ABCG2, OCT1, OCT2, OCTN1, and OCTN2 in the kidney of the hyperuricemic mice. Additionally, Siwu decoction remarkably reduced renal protein levels of NLRP3, ASC, Caspase-1, and IL-1β in the hyperuricemic mice. These results suggested that Siwu decoction exhibited anti-hyperuricemic and anti-inflammatory effects by inhibiting hepatic XOD activity, regulating renal organic ion transporter expression, and suppressing renal NLRP3 inflammasome activation, providing the evidence for its use in the treatment of hyperuricemia and associated kidney inflammation.

Anti-hyperuricemic and anti-inflammatory actions of vaticaffinol isolated from Dipterocarpus alatus in hyperuricemic mice

The present study was designed to examine the anti-hyperuricemic and anti-inflammatory effects and possible mechanisms of vaticaffinol, a resveratrol tetramer isolated from ethanol extracts of Dipterocarpus alatus, in oxonate-induced hyperuricemic mice. At 1 h after 250 mg·kg^(-1) potassium oxonate was given, vaticaffinol at 20, 40, and 60 mg·kg^(-1) was intragastrically administered to hyperuricemic mice once daily for seven consecutive days. Vaticaffinol significantly decreased serum uric acid levels and improved kidney function in hyperuricemic mice. It inhibited hepatic activity of xanthine dehydrogenase(XDH) and xanthine oxidase(XOD), regulated renal m RNA and protein levels of urate transporter 1(URAT1), glucose transporter 9(GLUT9), organic anion transporter 1(OAT1), organic cation transporter 1(OCT1), OCT2, organic cation/carnitine transporter 1(OCTN1), and OCTN2 in hyperuricemic mice. Moreover, vaticaffinol markedly down-regulated renal protein levels of NOD-like receptor 3(NLRP3), apoptosis-associated speck-like(ASC), and Caspase-1, resulting in the reduction of interleukin(IL)-1β, IL-18, IL-6 and tumor necrosis factor-α(TNF-α) levels in this animal model. Additionally, HPLC and LC-MS analyses clearly testified the presence of vaticaffinol in the crude extract. These results suggest that vaticaffinol may be useful for the prevention and treatment of hyperuricemia with kidney inflammation.