肾脏尿酸转运体的研究进展

尿酸是人体内嘌呤代谢的终产物。在肝脏合成后,正常情况下约70%的尿酸在肾脏分泌,而一小部分则被分泌到肠内。肾脏是血尿酸稳态调节的主要器官,其调控依赖于尿酸转运体的转运。尿酸代谢紊乱或转运异常将导致高尿酸血症、痛风、痛风性肾结石等疾病。本文对肾脏尿酸转运体的研究进展进行综述。     

高尿酸血症和痛风的遗传学研究进展

痛风是由高尿酸血症引发的一种常见炎性关节炎,受遗传因素和环境因素共同作用。早期研究表明,PRPS1和HPRT1等单基因稀有突变会引起嘌呤合成代谢紊乱,从而引发高尿酸血症和痛风。近年来,全基因组关联分析(Genome-wide association studies,GWAS)已检出多个导致高尿酸血症和痛风的易感位点及相关候选基因。其中SLC2A9、SLC22A11和SLC22A12基因功能缺失性突变可引起遗传性低尿酸血症,而过表达则会加强尿酸的重吸收。ABCG2、SLC17A1和SLC17A3基因功能缺陷型变异会降低肾脏和肠道对尿酸的排泄量。因此,诱发尿酸排泄障碍(高重吸收和低排泄)的基因变异是影响高尿酸血症和痛风的主要遗传因素。另外,抑制-激活生长因子系统、转录因子、细胞骨架以及基因和环境的互作等因素也一定程度影响血液尿酸水平。在中国汉族人群中,两个新发现的易感基因RFX3和KCNQ1可能造成免疫应答受损和胰岛B细胞功能缺陷,从而直接或间接引起高尿酸酸血症和痛风。本文系统综述了高尿酸血症和痛风的遗传学研究,以促进人们对高尿酸血症和痛风发病机理的理解。     

高尿酸血症与高血压病相关性的研究进展

尿酸是人体内嘌呤代谢的最终产物,当尿酸生成增多和/或排出减少时,均可引起血中尿酸盐浓度增高。当血尿酸水平男性大于7.0 mg/dl,女性大于6.0 mg/dl称为高尿酸血症。作为嘌呤代谢紊乱所致疾病,高尿酸血症以往仅侧重于痛风性关节炎、痛风石沉积和肾尿酸结石形成等的诊断与治疗。目前新近研究表明:高尿酸血症可能是高血压病的独立危险因素之一且尿酸水平增高通常早于高血压的发生与进展,干预尿酸水平有望成为高血压治疗的新靶点,随着高血压研究的全球化深入,对于尿酸及尿酸水平增高的流行病学、基础学与临床方面的研究也日益备受关注。基于此,本文对尿酸的合成与代谢;高尿酸血症成因及其与高血压的流行病学研究;高尿酸血症通过引发一氧化氮合成水平减低、血管平滑肌细胞生物学行为改变、机体炎症与氧化应激反应及肾素-血管紧张素系统激活等方面所致高血压的发病机制;高尿酸血症干预治疗对于高血压病的转归进行简要综述。     

痛风性关节炎动物模型的研究现状与展望

痛风是由于机体嘌呤代谢紊乱,导致血内尿酸增高和/或肾脏排泄尿酸减少,从而引起尿酸盐在组织沉积的疾病,目前尚未见在实验动物中复制出类似人类的痛风性关节炎模型。通过对目前国内外高尿酸血症及痛风模型复制的方法、机制和应用的研究,分析各自的特点及不足之处,并提出复制更加符合临床的高尿酸血症及痛风性关节炎动物模型的展望与设想。     

基于肠道菌群防治高尿酸血症的研究进展

高尿酸血症是由嘌呤代谢异常引起尿酸生成过多和(或)排泄减少导致血尿酸超出正常范围的代谢性疾病.目前研究已证实,促进尿酸合成的酶在肠道中高表达,人体1/3的尿酸经肠道排泄.随着微生物学研究的快速发展,肠道菌群的研究也逐渐深入,发现高尿酸血症患者肠道菌群的结构和数量均发生变化,肠道菌群可能是高尿酸血症的肠道触发因素.肠道菌...     

微生物来源的尿酸氧化酶的研究进展及应用前景

尿酸氧化酶是一种重要的医药用酶,它催化嘌呤代谢途径中的尿酸氧化生成尿囊素和过氧化氢,因而被广泛用于治疗痛风,检测血液尿酸浓度,预防和治疗由于肿瘤化学治疗引起的高尿酸血症。综述了尿酸氧化酶的来源、酶学性质、基因克隆与表达及其用途,并对其在应用中存在的问题和前景作了展望。     

肠道上皮LncRNA在肠道菌群与痛风间的桥梁作用

痛风作为一种代谢性疾病,其病因主要为嘌呤核苷酸代谢紊乱及尿酸排泄障碍,临床表现主要是高尿酸血症以及不定期发作的急性关节疼痛,而单钠尿酸结晶沉积引起炎症反应是急性关节疼痛的关键环节。长链非编码RNA（long-chain non-coding RNA,LncRNA）是一类不编码蛋白质的调控RNA,其在单钠尿酸结晶沉积引起的炎症反应中起着主要调控作用。近年来,随着肠道菌群概念的提出,众多学者发现肠道菌群在痛风的发生发展中发挥着主要的调控作用。正常人与高尿酸血症患者在肠道上皮LncRNA种类和数量上存在显著差异。在临床工作中,调节肠道菌群对控制血尿酸水平具有重要意义,因此推测通过调节肠道菌群从而调控肠道上皮LncRNA可能是一种控制血尿酸水平的有效方法,检测LncRNA的种类及数量可能成为一种诊断痛风及高尿酸血症的新方法。本文就痛风与LncRNA的关系、肠道菌群对高尿酸血症的影响、肠道黏膜屏障与LncRNA三个方面展开综述,揭示肠道上皮LncRNA在肠道菌群与痛风间的桥梁作用,为诊断痛风与控制血尿酸提供新的思路。

     

血清尿酸对心血管系统及神经退行性病变的影响

尿酸是人体嘌呤代谢的最终产物。高尿酸血症,即血清尿酸水平过高,是引发痛风的主要病因。越来越多的流行病学研究将高尿酸血症与心血管系统疾病和神经退行性病变紧密联系在一起。这些研究表明,炎性反应极有可能是高尿酸水平引发痛风的致病机制。同时,炎性反应与尿酸引起的心血管系统改变息息相关。尿酸钠晶体被认为通过Toll样受体家族诱发炎症反应诱导炎症的发生。此外,可溶性尿酸可以促进自由基的生成,起到促进氧化的作用。本综述总结了近期关于高尿酸血症和心血管系统疾病的流行病学研究,简要回顾了高尿酸血症在神经退行性病变中的作用,并描述了尿酸诱导的炎症产生机制。     

肠道菌群与高尿酸血症及痛风的相关性研究

高尿酸血症以及痛风的发病率持续升高,已经成为一个重大的公共卫生问题。肠道菌群的结构改变或失调可引起机体代谢紊乱,肠道微生态尤其与代谢性疾病的发生发展关系密切。目前研究发现高尿酸血症、痛风患者存在肠道菌群失调,降尿酸治疗后肠道菌群可发生相应改变,并且益生菌制剂具有降尿酸作用。本文概述高尿酸血症及痛风患者的肠道菌群特点,从高嘌呤及高果糖饮食对肠道菌群的影响、肠道参与嘌呤和尿酸的代谢、代谢性内毒素血症以及痛风相关炎症因子等方面探讨肠道菌群与高尿酸血症及痛风的关系,并展望肠道菌群可能成为未来诊治高尿酸血症以及痛风的一种新方法。     

几种天然产物对高尿酸血症大鼠血清尿酸水平的影响初探

目的:探讨几种天然产物对高尿酸血症大鼠血清尿酸水平及尿酸排泄的影响.方法:对wistar大鼠灌胃氧嗪酸钾和酵母膏,制作高尿酸血症大鼠动物模型.灌胃给药褐藻糖胶、柠檬酸钾和东哥阿里提取物,2周后采血并进行代谢实验,检测血清尿酸、尿素氮,24小时尿液体积、pH值、尿酸浓度及总量,分析三种活性物质对机体尿酸水平、尿酸排泄、肾脏功能的影响.结果:三种物质均可显著降低高尿酸血症模型大鼠的血清尿酸水平,其中东哥阿里提取物组的24小时排泄尿酸总量较模型组显著降低,褐藻糖胶对实验大鼠的血清尿素氮水平升高有抑制作用.结论:三种活性物质对高尿酸血症大鼠血清尿酸浓度有降低作用,其中褐藻糖胶对肾脏功能有保护作用,从而保证尿酸的顺利排泄,而东哥阿里在降低血尿酸水平的同时,24小时尿液中排泄的尿酸总量也显著低于模型对照组,其机制可能与抑制尿酸生成有关.     

非布司他对痛风合并高尿酸血症患者血清sICAM-1, ET-1 及尿酸水平的影响

目的:探讨非布司他对痛风合并高尿酸血症患者血清内皮素-1(ET-1)、细胞间粘附分子-1(ICAM-1)及尿酸水平的影响。方法:收集在我院就诊或住院治疗的80例痛风合并高尿酸血症患者,随机分为实验组和对照组,每组40例。对照组患者给予别嘌呤醇片治疗;实验组患者给予非布司他片治疗。观察并比较两组患者治疗前后血尿酸、s ICAM-1、ET-1水平及临床疗效。结果:与治疗前相比,两组患者治疗后的血尿酸、s ICAM-1、ET-1水平均显著降低(P0.05);与对照组相比,实验组患者的血尿酸、s ICAM-1、ET-1水平较低(P0.05),临床治疗总有效率较高(P0.05)。结论:非布司他能够降低痛风合并高尿酸血症的s ICAM-1、ET-1及尿酸水平,且临床疗效较好。     

Determination of uric acid in human saliva by high-performance liquid chromatography with amperometric electrochemical detection

The aim of the present study is to establish a highly sensitive method for the determination of uric acid (UA) in human saliva. The monitoring of UA levels in less invasive biological samples such as saliva is suggested for the diagnosis and therapy of gout, hyperuricemia, and the Lesch-Nyhan syndrome, and for detecting such conditions as alcohol dependence, obesity, diabetes, high cholesterol, high blood pressure, kidney disease, and heart disease. Reversed-phase high-performance liquid chromatography with electrochemical detection (HPLC-ED) was employed for the determination of UA obtained by solid-phase extraction from saliva. To quantify UA, we compared the ED efficiencies of an amperometric ED (Ampero-ED) with a single electrode and a coulometric ED (Coulo-ED) with a multiple electrode array. The results showed that the detection limits (S/N=3) were 3 nM for Ampero-ED and 6 nM for Coulo-ED, and the linearity of the calibration curves of 60-6000 nM had correlation coefficients exceeding 0.999. In addition, the total analytical time was 10 min. In the sample preparation of UA in saliva, an Oasis MAX solid-phase cartridge was used. The recoveries of UA spiked at 0.6 and 3 microM in saliva were above 95% with a relative standard deviation (RSD) of less than 15%. Therefore, the present method may be used in the routine and diagnostic determination of UA in human saliva.     

Recent developments in our understanding of the renal basis of hyperuricemia and the development of novel antihyperuricemic therapeutics

Although dietary, genetic, or disease-related excesses in urate production may contribute to hyperuricemia, impaired renal excretion of uric acid is the dominant cause of hyperuricemia in the majority of patients with gout. The aims of this review are to highlight exciting and clinically pertinent advances in our understanding of how uric acid is reabsorbed by the kidney under the regulation of urate transporter (URAT)1 and other recently identified urate transporters; to discuss urate-lowering agents in clinical development; and to summarize the limitations of currently available antihyperuricemic drugs. The use of uricosuric drugs to treat hyperuricemia in patients with gout is limited by prior urolothiasis or renal dysfunction. For this reason, our discussion focuses on the development of the novel xanthine oxidase inhibitor febuxostat and modified recombinant uricase preparations.     

Current Concepts of Hyperuricemia and Gout

Recent studies have confirmed that gout is an inborn error of metabolism. It has now become evident that the hyperuricemia associated with gout might occur either due to overproduction of uric acid, underexcretion of uric acid or a combination of these processes. Furthermore, patients with excessive purine synthesis may have a specific enzyme defect resulting in altered feedback inhibition of purine synthesis. A neurological disease manifest by mental retardation, choreo-athetosis, aggressive behavior, lip-biting and self-mutilation and associated with decidedly increased purine biosynthesis serves as a prototype of this kind of disorder. Other defects in regulation of purine biosynthesis have been postulated but their existence not yet confirmed.It has been demonstrated that urate crystals which are deposited from hyperuricemic body fluids set up an acute inflammatory reaction by means of a variety of chemical mediators. Thus, acute gouty arthritis is now recognized as an example of “crystal induced” synovitis.The treatment of gout consists of (1) the control of acute gouty attacks, and (2) the maintenance of normal serum uric acid concentrations. This latter may be achieved either with uricosuric drugs or with xanthine oxidase inhibition. With these principles in mind, it is now possible to avoid many of the severe crippling effects of gout and to restore the vast majority of gouty patients to useful and productive lives.     

An amperometric uric acid biosensor based on multiwalled carbon nanotube-gold nanoparticle composite

An amperometric uric acid biosensor was fabricated by immobilizing uricase (EC 1.7.3.3) onto gold nanoparticle (AuNP)/multiwalled carbon nanotube (MWCNT) layer deposited on Au electrode via carbodiimide linkage. Determination of uric acid was performed by oxidation of enzymically generated H₂O₂ at 0.4 V. The sensor showed optimal response within 7 s at 40 °C in 50 mM Tris–HCl buffer (pH 7.5). The linear working range of the biosensor was 0.01–0.8 mM. The limit of detection (LOD) was 0.01 mM. The sensor measured uric acid levels in serum of healthy individuals and persons suffering from gout. The analytical recoveries of the added uric acid, 10 and 20 mg L^–1, were 98.0% and 96.5%, respectively. Within- and between-batch coefficients of variation were less than 5.6% and less than 4.7%, respectively. A good correlation (r = 0.998) was obtained between serum uric acid values by the standard enzymic colorimetric method and the current method. A number of serum substances had practically no interference. The sensor was used in more than 200 assays and had a storage life of 120 days at 4 °C.     

血清尿酸水平与冠心病的相关性研究

目的:众多关于血清尿酸水平与冠心病发展预后的相关性研究结果不一。本研究旨在通过对上海市第一人民医院入院患者的临床资料分析,研究血清尿酸水平与冠心病之间关系。方法:选择2008年7月至2009年4月上海地区、汉族就诊于我院的患者(123例),按入选排除标准,将入院患者分为冠心病组和对照组,分析尿酸水平与冠心病的关系。结果:男性(81.4%vs 51.6%)、吸烟(49.2%vs 21.9%)、血清尿酸水平升高(6.10±1.2 mg/dl vs 5.37±1.5 mg/dl)为冠心病的危险因素,统计值分别为0.02,0.02,0.005。血尿酸水平升高与血管病变严重程度成正相关,除单支血管病变外,双支血管病变患者尿酸水平为(6.11±1.07)mg/dl,对照组为(5.37±1.55)mg/dl,P0.05,三支病变患者尿酸水平为(6.84±1.29)mg/dl,P0.05。结论:血清尿酸水平升高与冠心病的发生、及病变严重程度密切相关。对冠心病患者的预防和治疗中,应重视对尿酸水平的监测。尿酸水平能否作为冠心病患者预后、转归的预测因子以及降低尿酸水平的治疗能否给冠心病患者带来收益有待进一步的研究。     

肠道菌群失调与高尿酸血症关系的研究进展

高尿酸血症（hyperuricemia,HUA）是一种涉及肝、肾、肠等多个器官的代谢性疾病,因尿酸代谢异常而引起代谢障碍。尿酸在肝脏和肾脏中的代谢途径目前已经被阐明,但在肠道内的代谢途径尚未完全清晰。肠道菌群在人体肠道中定植,与宿主存在互惠共生的关系,在宿主的代谢和免疫调节中起着至关重要的作用。肠道菌群结构的变化可能引起代谢紊乱,肠道菌群参与嘌呤代谢酶的合成和炎症因子的释放,与HUA的发生发展密切相关。肠道菌群作为探讨HUA发病机制的切入点,已成为新的研究热点。本综述主要阐述HUA与肠道菌群之间的关系,探讨肠道菌群抗HUA的机制,如肠道菌群促进嘌呤和尿酸分解代谢,影响尿酸排泄,以及HUA引起的肠道炎症反应等,以期为通过调节肠道菌群来治疗HUA提供一定的依据。

     

The Pathophysiology of Hyperuricemia in Essential Hypertension: A Pilot Study

We have examined whether hyperuricemia in essential hypertension may be related to an increased insulin secretion thereby enhancing the tubular reabsorption of sodium and thus uric acid. Insulin hypersecretion, as elicited by the oral glucose tolerance test (OGTT), increased a mean of 5‐fold in 12 essential hypertensive patients. Urinary uric acid to creatinine ratio significantly diminished by a mean of 62% after the OGTT. Simultaneously, urinary sodium to creatinine ratio decreased by a mean of 54%. These results suggest that insulin may mediate uric acid underexcretion due to its tubular sodium retaining effect in essential hypertensive patients.