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Gefen AM, Zaritsky JJ. Review of childhood genetic nephrolithiasis and nephrocalcinosis. Front Genet 2024; 15:1381174. [PMID: 38606357 PMCID: PMC11007102 DOI: 10.3389/fgene.2024.1381174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 03/04/2024] [Indexed: 04/13/2024] Open
Abstract
Nephrolithiasis (NL) is a common condition worldwide. The incidence of NL and nephrocalcinosis (NC) has been increasing, along with their associated morbidity and economic burden. The etiology of NL and NC is multifactorial and includes both environmental components and genetic components, with multiple studies showing high heritability. Causative gene variants have been detected in up to 32% of children with NL and NC. Children with NL and NC are genotypically heterogenous, but often phenotypically relatively homogenous, and there are subsequently little data on the predictors of genetic childhood NL and NC. Most genetic diseases associated with NL and NC are secondary to hypercalciuria, including those secondary to hypercalcemia, renal phosphate wasting, renal magnesium wasting, distal renal tubular acidosis (RTA), proximal tubulopathies, mixed or variable tubulopathies, Bartter syndrome, hyperaldosteronism and pseudohyperaldosteronism, and hyperparathyroidism and hypoparathyroidism. The remaining minority of genetic diseases associated with NL and NC are secondary to hyperoxaluria, cystinuria, hyperuricosuria, xanthinuria, other metabolic disorders, and multifactorial etiologies. Genome-wide association studies (GWAS) in adults have identified multiple polygenic traits associated with NL and NC, often involving genes that are involved in calcium, phosphorus, magnesium, and vitamin D homeostasis. Compared to adults, there is a relative paucity of studies in children with NL and NC. This review aims to focus on the genetic component of NL and NC in children.
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Affiliation(s)
- Ashley M. Gefen
- Phoenix Children’s Hospital, Department of Pediatrics, Division of Nephrology, Phoenix, AZ, United States
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2
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Lee H, Kang D, Lee H, Yim J, Kim M, Park CW. Renal hypouricemia as the cause of exercise-induced acute kidney injury. Kidney Res Clin Pract 2023; 42:534-537. [PMID: 37448289 PMCID: PMC10407641 DOI: 10.23876/j.krcp.23.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/20/2023] [Indexed: 07/15/2023] Open
Affiliation(s)
- Haeun Lee
- Division of Nephrology, Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Republic of Korea
| | - Donghyuk Kang
- Department of Nephrology and Hypertension, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Hanbi Lee
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary’s Hospital, Seoul, Republic of Korea
| | - Jisook Yim
- Department of Laboratory Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Myungshin Kim
- Department of Laboratory Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Cheol Whee Park
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary’s Hospital, Seoul, Republic of Korea
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Hosoya T, Uchida S, Shibata S, Tomioka NH, Matsumoto K, Hosoyamada M. Xanthine Oxidoreductase Inhibitors Suppress the Onset of Exercise-Induced AKI in High HPRT Activity Urat1- Uox Double Knockout Mice. J Am Soc Nephrol 2022; 33:326-341. [PMID: 34799437 PMCID: PMC8819989 DOI: 10.1681/asn.2021050616] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/09/2021] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Hereditary renal hypouricemia type 1 (RHUC1) is caused by URAT1/SLC22A12 dysfunction, resulting in urolithiasis and exercise-induced AKI (EIAKI). However, because there is no useful experimental RHUC1 animal model, the precise pathophysiologic mechanisms underlying EIAKI have yet to be elucidated. We established a high HPRT activity Urat1-Uox double knockout (DKO) mouse as a novel RHUC1 animal model for investigating the cause of EIAKI and the potential therapeutic effect of xanthine oxidoreductase inhibitors (XOIs). METHODS The novel Urat1-Uox DKO mice were used in a forced swimming test as loading exercise to explore the onset mechanism of EIAKI and evaluate related purine metabolism and renal injury parameters. RESULTS Urat1-Uox DKO mice had uricosuric effects and elevated levels of plasma creatinine and BUN as renal injury markers, and decreased creatinine clearance observed in a forced swimming test. In addition, Urat1-Uox DKO mice had increased NLRP3 inflammasome activity and downregulated levels of Na+-K+-ATPase protein in the kidney, as Western blot analysis showed. Finally, we demonstrated that topiroxostat and allopurinol, XOIs, improved renal injury and functional parameters of EIAKI. CONCLUSIONS Urat1-Uox DKO mice are a useful experimental animal model for human RHUC1. The pathogenic mechanism of EIAKI was found to be due to increased levels of IL-1β via NLRP3 inflammasome signaling and Na+-K+-ATPase dysfunction associated with excessive urinary urate excretion. In addition, XOIs appear to be a promising therapeutic agent for the treatment of EIAKI.
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Affiliation(s)
- Takuji Hosoya
- Department of Human Physiology and Pathology, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan,Biological Research Department, Research Institute, Fuji Yakuhin Co., Ltd., Saitama, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Naoko H. Tomioka
- Department of Human Physiology and Pathology, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Koji Matsumoto
- Biological Research Department, Research Institute, Fuji Yakuhin Co., Ltd., Saitama, Japan
| | - Makoto Hosoyamada
- Department of Human Physiology and Pathology, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
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Jung SW, Kim SM, Kim YG, Lee SH, Moon JY. Uric acid and inflammation in kidney disease. Am J Physiol Renal Physiol 2020; 318:F1327-F1340. [PMID: 32223310 DOI: 10.1152/ajprenal.00272.2019] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Asymptomatic hyperuricemia is frequently observed in patients with kidney disease. Although a substantial number of epidemiologic studies have suggested that an elevated uric acid level plays a causative role in the development and progression of kidney disease, whether hyperuricemia is simply a result of decreased renal excretion of uric acid or is a contributor to kidney disease remains a matter of debate. Over the last two decades, multiple experimental studies have expanded the knowledge of the biological effects of uric acid beyond its role in gout. In particular, uric acid induces immune system activation and alters the characteristics of resident kidney cells, such as tubular epithelial cells, endothelial cells, and vascular smooth muscle cells, toward a proinflammatory and profibrotic state. These findings have led to an increased awareness of uric acid as a potential and modifiable risk factor in kidney disease. Here, we discuss the effects of uric acid on the immune system and subsequently review the effects of uric acid on the kidneys mainly in the context of inflammation.
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Affiliation(s)
- Su Woong Jung
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
| | - Su-Mi Kim
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
| | - Yang Gyun Kim
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
| | - Sang-Ho Lee
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
| | - Ju-Young Moon
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
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5
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Hypouricemia: what the practicing rheumatologist should know about this condition. Clin Rheumatol 2019; 39:135-147. [PMID: 31650389 DOI: 10.1007/s10067-019-04788-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/27/2019] [Accepted: 09/21/2019] [Indexed: 12/15/2022]
Abstract
We presented an update in the field of hypouricemia, which is defined as a serum urate concentration of < 2 mg/dL (119 μmol/L), for the practicing rheumatologist, who usually is the consulting physician in cases of disorders of urate metabolism. We performed a narrative review through a literature search for original and review articles in the field of human hypouricemia published between January 1950 and July 2018. We divided the etiology of hypouricemia into two main categories: those associated with a decrease in urate production and those promoting the elimination of urate via the kidneys. The most common conditions associated with these categories are discussed. Furthermore, the etiology of hypouricemia may be associated with certain medications prescribed by the practicing rheumatologists, such as the following: urate-lowering drugs (allopurinol and febuxostat); recombinant uricase (pegloticase); uricosuric agents (probenecid, benzbromarone); urate transporter URAT1 inhibitor (lesinurad); angiotensin II receptor blocker (losartan); fenofibrate; high-dose trimethoprim-sulfamethoxazole; some NSAID; and high-dose salicylate therapy. The rheumatologist is considered an expert in the metabolism of urate and its associated pathological conditions. Therefore, specialists must recognize hypouricemia as a biomarker of various pathological and potentially harmful conditions, highlighting the importance of conducting a deeper clinical investigation to reach a more accurate diagnosis and treatment.
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Nigam SK. The SLC22 Transporter Family: A Paradigm for the Impact of Drug Transporters on Metabolic Pathways, Signaling, and Disease. Annu Rev Pharmacol Toxicol 2019; 58:663-687. [PMID: 29309257 DOI: 10.1146/annurev-pharmtox-010617-052713] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The SLC22 transporter family consists of more than two dozen members, which are expressed in the kidney, the liver, and other tissues. Evolutionary analysis indicates that SLC22 transporters fall into at least six subfamilies: OAT (organic anion transporter), OAT-like, OAT-related, OCT (organic cation transporter), OCTN (organic cation/carnitine transporter), and OCT/OCTN-related. Some-including OAT1 [SLC22A6 or NKT (novel kidney transporter)] and OAT3 (SLC22A8), as well as OCT1 (SLC22A1) and OCT2 (SLC22A2)-are widely studied drug transporters. Nevertheless, analyses of knockout mice and other data indicate that SLC22 transporters regulate key metabolic pathways and levels of signaling molecules (e.g., gut microbiome products, bile acids, tricarboxylic acid cycle intermediates, dietary flavonoids and other nutrients, prostaglandins, vitamins, short-chain fatty acids, urate, and ergothioneine), as well as uremic toxins associated with chronic kidney disease. Certain SLC22 transporters-such as URAT1 (SLC22A12) and OCTN2 (SLC22A5)-are mutated in inherited metabolic diseases. A new systems biology view of transporters is emerging. As proposed in the remote sensing and signaling hypothesis, SLC22 transporters, together with other SLC and ABC transporters, have key roles in interorgan and interorganism small-molecule communication and, together with the neuroendocrine, growth factor-cytokine, and other homeostatic systems, regulate local and whole-body homeostasis.
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Affiliation(s)
- Sanjay K Nigam
- Departments of Pediatrics and Medicine, University of California, San Diego, La Jolla, California 92093, USA;
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Polymorphisms of ABCG2 and SLC22A12 Genes Associated with Gout Risk in Vietnamese Population. ACTA ACUST UNITED AC 2019; 55:medicina55010008. [PMID: 30621105 PMCID: PMC6359270 DOI: 10.3390/medicina55010008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/13/2018] [Accepted: 01/03/2019] [Indexed: 12/20/2022]
Abstract
Background and objective: Gout is a common form of inflammatory arthritis caused by the crystallization of uric acid. Previous studies have demonstrated that the genetic predisposition of gout varies in different ethnic populations. However the association study of genetic variants with gout remains unknown in the Vietnamese population. Our study aimed to assess the relationship between polymorphisms in ABCG2 and SLC22A12 and gout susceptibility in Vietnamese. Materials and methods: Genomic DNA was extracted from blood of a total of 170 patients with gout and 351 healthy controls. We genotyped single nucleotide polymorphisms (SNPs): rs72552713, rs12505410 of the ABCG2 gene and rs11231825, rs7932775 of the SLC22A12 gene using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and then confirmed 10% of randomly selected subjects by Sanger sequencing. Results: Three SNPs (rs72552713 and rs12505410 and rs11231825) were in accordance with Hardy–Weinberg Equilibrium (HWE) (p > 0.05) while rs7932775 was not (p < 0.05). For rs72552713, CT genotype was significantly different between gout patient and control groups (p < 0.001) and the T allele was associated with an increased risk of gout (OR = 21.19; 95% CI: 3.00–918.96; p < 0.001). Serum uric acid and hyperuricemia differed significantly between CC and CT genotype groups (p = 0.004 and 0.008, respectively). For rs11231825, a protective effect against gout risk was identified in the presence of the C allele when compared with the T allele (OR = 0.712; 95% CI: 0.526–0.964 p = 0.0302). In contrast, no significant difference of allele frequencies between gout patients and controls was detected for rs12505410 (p > 0.05). However, significant differences in serum uric acid and systolic blood pressure were obtained among gout patients. Conclusion: Our results suggest that ABCG2 rs72552713 and SLC22A12 rs11231825 are likely associated with gout in the Vietnamese population in which T allele may be a risk factor for gout susceptibility.
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Zhou Z, Ma L, Zhou J, Song Z, Zhang J, Wang K, Chen B, Pan D, Li Z, Li C, Shi Y. Renal hypouricemia caused by novel compound heterozygous mutations in the SLC22A12 gene: a case report with literature review. BMC MEDICAL GENETICS 2018; 19:142. [PMID: 30097038 PMCID: PMC6086067 DOI: 10.1186/s12881-018-0595-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/26/2018] [Indexed: 12/20/2022]
Abstract
Background Renal hypouricemia (RHUC) is a heterogeneous genetic disorder that is characterized by decreased serum uric acid concentration and increased fractional excretion of uric acid. Previous reports have revealed many functional mutations in two urate transporter genes, SLC22A12 and/or SLC2A9, to be the causative genetic factors of this disorder. However, there are still unresolved patients, suggesting the existence of other causal genes or new mutations. Here, we report an RHUC patient with novel compound heterozygous mutations in the SLC22A12 gene. Case presentation A 27-year-old female presenting with recurrent hypouricemia during routine checkups was referred to our hospital. After obtaining the patient’s consent, both the patient and her healthy parents were analyzed using whole-exome sequencing (WES) and Sanger sequencing to discover and validate causal mutations, respectively. The prioritization protocol of WES screened out two mutations of c.269G > A/p.R90H and c.1289_1290insGG/p.M430fsX466, which are both located in the SLC22A12 gene, in the patient. Sanger sequencing further confirmed that the patient’s heterozygous c.269G > A/p.R90H mutation, which has been reported previously, derived from her mother, and the heterozygous c.1289_1290insGG/p.M430fsX466 mutation, which was found for the first time, derived from her father. p.R90H, which is highly conserved among different species, may decrease the stability of this domain and was considered to be almost damaging in silicon analysis. p.M430fsX466 lacks the last three transmembrane domains, including the tripeptide motif (S/T)XΦ (X = any amino acid and Φ = hydrophobic residue), at the C-terminal, which interact with scaffolding protein PDZK1 and thus will possibly lead to weak functioning of urate transport through the disruption of the “transporter complex” that is formed by URAT1 and PDZK1. Conclusions We report a Chinese patient with RHUC, which was caused by compound heterozygous mutations of the SLC22A12 gene, using WES and Sanger sequencing for the first time. Mutation-induced structural instability or malfunction of the urate transporter complex may be the main mechanisms for this hereditary disorder. Electronic supplementary material The online version of this article (10.1186/s12881-018-0595-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhaowei Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Lidan Ma
- Shandong Gout Clinical Medical Center, Qingdao, 266003, People's Republic of China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266003, People's Republic of China.,The Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Juan Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Zhijian Song
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Jinmai Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Ke Wang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Boyu Chen
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Dun Pan
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China
| | - Zhiqiang Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China.,Biomedical Sciences Institute, the Qingdao Branch of SJTU Bio-X Institutes, Qingdao University, Qingdao, 266003, People's Republic of China
| | - Changgui Li
- Shandong Gout Clinical Medical Center, Qingdao, 266003, People's Republic of China. .,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266003, People's Republic of China. .,The Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China. .,Metabolic Disease Institute, Qingdao University, Qingdao, 266003, People's Republic of China.
| | - Yongyong Shi
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, No. 1954 Huashan Road, Shanghai, 200030, People's Republic of China. .,Shandong Gout Clinical Medical Center, Qingdao, 266003, People's Republic of China. .,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266003, People's Republic of China. .,Biomedical Sciences Institute, the Qingdao Branch of SJTU Bio-X Institutes, Qingdao University, Qingdao, 266003, People's Republic of China.
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9
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Serine Protease Inhibitor Kazal Type I (SPINK1) Mutation: A Risk Factor for Early-onset Chronic Pancreatitis? J Pediatr Gastroenterol Nutr 2018; 67:e40. [PMID: 29746346 DOI: 10.1097/mpg.0000000000002024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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10
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Zhu W, Deng Y, Zhou X. Multiple Membrane Transporters and Some Immune Regulatory Genes are Major Genetic Factors to Gout. Open Rheumatol J 2018; 12:94-113. [PMID: 30123371 PMCID: PMC6062909 DOI: 10.2174/1874312901812010094] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/30/2018] [Accepted: 06/20/2018] [Indexed: 01/10/2023] Open
Abstract
Gout is a common form of inflammatory arthritis caused by hyperuricemia and the deposition of Monosodium Urate (MSU) crystals. It is also considered as a complex disorder in which multiple genetic factors have been identified in association with its susceptibility and/or clinical outcomes. Major genes that were associated with gout include URAT1, GLUT9, OAT4, NPT1 (SLC17A1), NPT4 (SLC17A3), NPT5 (SLC17A4), MCT9, ABCG2, ABCC4, KCNQ1, PDZK1, NIPAL1, IL1β, IL-8, IL-12B, IL-23R, TNFA, MCP-1/CCL2, NLRP3, PPARGC1B, TLR4, CD14, CARD8, P2X7R, EGF, A1CF, HNF4G and TRIM46, LRP2, GKRP, ADRB3, ADH1B, ALDH2, COMT, MAOA, PRKG2, WDR1, ALPK1, CARMIL (LRRC16A), RFX3, BCAS3, CNIH-2, FAM35A and MYL2-CUX2. The proteins encoded by these genes mainly function in urate transport, inflammation, innate immunity and metabolism. Understanding the functions of gout-associated genes will provide important insights into future studies to explore the pathogenesis of gout, as well as to develop targeted therapies for gout.
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Affiliation(s)
- Weifeng Zhu
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Nanchang University, Nanchang, China.,Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yan Deng
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.,Department of Ophthalmology of Children, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xiaodong Zhou
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
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11
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Benn CL, Dua P, Gurrell R, Loudon P, Pike A, Storer RI, Vangjeli C. Physiology of Hyperuricemia and Urate-Lowering Treatments. Front Med (Lausanne) 2018; 5:160. [PMID: 29904633 PMCID: PMC5990632 DOI: 10.3389/fmed.2018.00160] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/08/2018] [Indexed: 12/18/2022] Open
Abstract
Gout is the most common form of inflammatory arthritis and is a multifactorial disease typically characterized by hyperuricemia and monosodium urate crystal deposition predominantly in, but not limited to, the joints and the urinary tract. The prevalence of gout and hyperuricemia has increased in developed countries over the past two decades and research into the area has become progressively more active. We review the current field of knowledge with emphasis on active areas of hyperuricemia research including the underlying physiology, genetics and epidemiology, with a focus on studies which suggest association of hyperuricemia with common comorbidities including cardiovascular disease, renal insufficiency, metabolic syndrome and diabetes. Finally, we discuss current therapies and emerging drug discovery efforts aimed at delivering an optimized clinical treatment strategy.
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Affiliation(s)
| | - Pinky Dua
- Pfizer Ltd., Cambridge, United Kingdom
| | | | | | - Andrew Pike
- DMPK, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | - R Ian Storer
- IMED Biotech Unit, Medicinal Chemistry, Discovery Sciences, AstraZeneca, Cambridge, United Kingdom
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12
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Marchetti M, Liuzzi A, Fermi B, Corsini R, Folli C, Speranzini V, Gandolfi F, Bettati S, Ronda L, Cendron L, Berni R, Zanotti G, Percudani R. Catalysis and Structure of Zebrafish Urate Oxidase Provide Insights into the Origin of Hyperuricemia in Hominoids. Sci Rep 2016; 6:38302. [PMID: 27922051 PMCID: PMC5138847 DOI: 10.1038/srep38302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/03/2016] [Indexed: 01/24/2023] Open
Abstract
Urate oxidase (Uox) catalyses the first reaction of oxidative uricolysis, a three-step enzymatic pathway that allows some animals to eliminate purine nitrogen through a water-soluble compound. Inactivation of the pathway in hominoids leads to elevated levels of sparingly soluble urate and puts humans at risk of hyperuricemia and gout. The uricolytic activities lost during evolution can be replaced by enzyme therapy. Here we report on the functional and structural characterization of Uox from zebrafish and the effects on the enzyme of the missense mutation (F216S) that preceded Uox pseudogenization in hominoids. Using a kinetic assay based on the enzymatic suppression of the spectroscopic interference of the Uox reaction product, we found that the F216S mutant has the same turnover number of the wild-type enzyme but a much-reduced affinity for the urate substrate and xanthine inhibitor. Our results indicate that the last functioning Uox in hominoid evolution had an increased Michaelis constant, possibly near to upper end of the normal range of urate in the human serum (~300 μM). Changes in the renal handling of urate during primate evolution can explain the genetic modification of uricolytic activities in the hominoid lineage without the need of assuming fixation of deleterious mutations.
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Affiliation(s)
| | - Anastasia Liuzzi
- Department of Life Sciences, University of Parma, 43124, Parma, Italy
| | - Beatrice Fermi
- Department of Life Sciences, University of Parma, 43124, Parma, Italy
| | - Romina Corsini
- Department of Life Sciences, University of Parma, 43124, Parma, Italy
| | - Claudia Folli
- Department of Food Science University of Parma, 43124, Parma, Italy
| | | | | | - Stefano Bettati
- Department of Neurosciences, University of Parma, 43124, Parma, Italy
| | - Luca Ronda
- Department of Neurosciences, University of Parma, 43124, Parma, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Rodolfo Berni
- Department of Life Sciences, University of Parma, 43124, Parma, Italy
| | - Giuseppe Zanotti
- Department of Biology, University of Padova, 35121, Padova, Italy
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13
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Shen H, Feng C, Jin X, Mao J, Fu H, Gu W, Liu A, Shu Q, Du L. Recurrent exercise-induced acute kidney injury by idiopathic renal hypouricemia with a novel mutation in the SLC2A9 gene and literature review. BMC Pediatr 2014; 14:73. [PMID: 24628802 PMCID: PMC3984694 DOI: 10.1186/1471-2431-14-73] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/06/2014] [Indexed: 11/15/2022] Open
Abstract
Background Idiopathic renal hypouricemia (iRHUC) is an autosomal recessive hereditary disorder, characterized by impaired tubular uric acid transport, re-absorption insufficiency and/or the acceleration of secretions. Some patients present with severe complications, such as exercise-induced acute kidney injury (EIAKI) and nephrolithiasis. Case presentation Herein, we report the case of a girl with severe iRHUC (serum urate 0.05 mg/dL, fractional excretion of uric acid 295.99%) associated with recurrent EIAKI, in whom the disease was caused by a homozygous mutation (g.68G > A in exon 3) in the SLC2A9 gene. Her family members (father, mother and brother) carried the same mutation but were heterozygous, without any signs of severe hypouricemia. Conclusions Our findings indicate that iRHUC is a rare disorder but that it should also be considered in patients with EIAKI, especially in those patients who manifest with moderately elevated or normal serum concentrations of uric acid during the acute phase of AKI. Mutational screening of the SLC2A9 gene is necessary for the diagnosis of iRHUC, and homozygous mutations of the SLC2A9 alleles can cause severe hypouricemia. Careful attention should be paid to any signs of hypouricemia during the recovery phase of AKI and long-term follow-up.
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Affiliation(s)
| | | | | | - Jianhua Mao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China.
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Kaito H, Ishimori S, Nozu K, Shima Y, Nakanishi K, Yoshikawa N, Iijima K. Molecular background of urate transporter genes in patients with exercise-induced acute kidney injury. Am J Nephrol 2013; 38:316-20. [PMID: 24107611 DOI: 10.1159/000355430] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/30/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND/AIMS Exercise-induced acute renal failure [exercise-induced acute kidney injury (EI-AKI)] is defined as AKI due to heavy anaerobic exercise. Although hypouricemia is known to be a risk factor for the onset of EI-AKI, a direct causal link between EI-AKI and serum uric acid has not been established. This study aimed to analyze urate transporter genes in patients with EI-AKI and its molecular mechanism. METHODS Genomic DNA and total RNA were isolated from peripheral blood leukocytes of patients with a history of EI-AKI. Mutations were analyzed by PCR and a direct sequencing method. We first analyzed the SLC22A12 gene, and then the SLC2A9 gene if no mutations were found in SLC22A12. RESULTS Seventeen patients were enrolled in this study and 16 had mutations: 15 in SLC22A12 and 1 in SLC2A9. Fourteen (82.4%) patients showed hypouricemia, and all of the patients with hypouricemia had either homozygous or compound heterozygous mutations in SLC22A12 or SLC2A9, which confirmed that all of them had renal hypouricemia. Two patients had heterozygous mutations of SLC22A12, and they were not accompanied by hypouricemia. One patient was found to have no mutations in SLC22A12 or SLC2A9. CONCLUSION We were able to determine the genetic background of urate transporter genes in patients with EI-AKI. Decreased function of urate transporters, rather than decreased serum uric acid levels, may be of great importance for the onset of EI-AKI.
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Affiliation(s)
- Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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Bobulescu IA, Moe OW. Renal transport of uric acid: evolving concepts and uncertainties. Adv Chronic Kidney Dis 2012; 19:358-71. [PMID: 23089270 PMCID: PMC3619397 DOI: 10.1053/j.ackd.2012.07.009] [Citation(s) in RCA: 240] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 07/17/2012] [Indexed: 02/07/2023]
Abstract
In addition to its role as a metabolic waste product, uric acid has been proposed to be an important molecule with multiple functions in human physiologic and pathophysiologic processes and may be linked to human diseases beyond nephrolithiasis and gout. Uric acid homeostasis is determined by the balance between production, intestinal secretion, and renal excretion. The kidney is an important regulator of circulating uric acid levels by reabsorbing about 90% of filtered urate and being responsible for 60% to 70% of total body uric acid excretion. Defective renal handling of urate is a frequent pathophysiologic factor underpinning hyperuricemia and gout. Despite tremendous advances over the past decade, the molecular mechanisms of renal urate transport are still incompletely understood. Many transport proteins are candidate participants in urate handling, with URAT1 and GLUT9 being the best characterized to date. Understanding these transporters is increasingly important for the practicing clinician as new research unveils their physiologic characteristics, importance in drug action, and genetic association with uric acid levels in human populations. The future may see the introduction of new drugs that act specifically on individual renal urate transporters for the treatment of hyperuricemia and gout.
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Affiliation(s)
- Ion Alexandru Bobulescu
- Departments of Internal Medicine and Physiology and the Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-8856, USA.
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Lee J, Lee SW, Lee JW, Chin HJ, Joo KW, Kim YS, Ahn C, Kim S, Cho JY, Han JS. Clinical characteristics of acute renal failure with severe loin pain and patchy renal vasoconstriction. Kidney Res Clin Pract 2012; 31:170-6. [PMID: 26894023 PMCID: PMC4716092 DOI: 10.1016/j.krcp.2012.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/14/2012] [Accepted: 05/23/2012] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Acute renal failure (ARF) with severe loin pain and patchy renal vasoconstriction (PRV) is a syndrome presenting with sudden loin pain after anaerobic exercise. We aimed to investigate the clinical characteristics and the efficacy of diagnostic imaging studies of patients with this syndrome. METHODS We retrospectively selected 17 patients with ARF accompanied by loin or abdominal pain who showed multiple patchy wedge-shaped delayed contrast enhancements on a computerized tomography scan. Information about the clinical characteristics, including the nature of pain and combined symptoms, suspected causes, such as exercise, drug or alcohol intake, and renal hypouricemia, and the results of laboratory and imaging tests were gathered. RESULTS The mean age of patients with episodes of ARF accompanied by loin pain was 23.0±6.5 (range 16-35) years old. Pain was mainly located in the loin (70.6%) or abdominal area (76.5%) and continued for approximately 3.5±4.0 days. Exercise was suspected as a primary cause of disease in 12 (70.6%) patients. Maximal serum creatinine was 5.42±3.16 (1.4-12.1) mg/dL 3.1±1.8 (1-7) days after the onset of pain. The peak level of serum uric acid was 9.41±2.91 (6.0-15.8) mg/dL. All of the patients recovered to near-normal renal function, and one patient showed hypouricemia after recovery. CONCLUSION ARF with severe loin pain and PRV can present with loin or abdominal pain, even without a history of anaerobic exercise. Careful history taking and appropriate imaging studies are critical in the diagnosis and management of this syndrome.
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Affiliation(s)
- Jeonghwan Lee
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Seong Woo Lee
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jae Wook Lee
- Epithelial Systems Biology Laboratory, National Heart Lung and Blood Institute, National Institute of Health, Bethesda, Maryland, United States
| | - Ho Jun Chin
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kwon Wook Joo
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Yon Su Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Curie Ahn
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Suhnggwon Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jeong Yeon Cho
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Jin Suk Han
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
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17
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Uric Acid Nephrolithiasis: Basic and Clinical Aspects. Urolithiasis 2012. [DOI: 10.1007/978-1-4471-4387-1_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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The Genetics of Kidney Stones. Urolithiasis 2012. [DOI: 10.1007/978-1-4471-4387-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Tasic V, Hynes AM, Kitamura K, Cheong HI, Lozanovski VJ, Gucev Z, Jutabha P, Anzai N, Sayer JA. Clinical and functional characterization of URAT1 variants. PLoS One 2011; 6:e28641. [PMID: 22194875 PMCID: PMC3241677 DOI: 10.1371/journal.pone.0028641] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 11/11/2011] [Indexed: 12/27/2022] Open
Abstract
Idiopathic renal hypouricaemia is an inherited form of hypouricaemia, associated with abnormal renal handling of uric acid. There is excessive urinary wasting of uric acid resulting in hypouricaemia. Patients may be asymptomatic, but the persistent urinary abnormalities may manifest as renal stone disease, and hypouricaemia may manifest as exercise induced acute kidney injury. Here we have identified Macedonian and British patients with hypouricaemia, who presented with a variety of renal symptoms and signs including renal stone disease, hematuria, pyelonephritis and nephrocalcinosis. We have identified heterozygous missense mutations in SLC22A12 encoding the urate transporter protein URAT1 and correlate these genetic findings with functional characterization. Urate handling was determined using uptake experiments in HEK293 cells. This data highlights the importance of the URAT1 renal urate transporter in determining serum urate concentrations and the clinical phenotypes, including nephrolithiasis, that should prompt the clinician to suspect an inherited form of renal hypouricaemia.
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Affiliation(s)
- Velibor Tasic
- Medical School, University Children's Hospital, Skopje, Macedonia
| | - Ann Marie Hynes
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, United Kingdom
| | - Kenichiro Kitamura
- Department of Nephrology, Kumamoto University Graduate School of Life Sciences, Kumamoto, Japan
| | - Hae Il Cheong
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | | | - Zoran Gucev
- Medical School, University Children's Hospital, Skopje, Macedonia
| | - Promsuk Jutabha
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Mibu, Tochigi, Japan
| | - Naohiko Anzai
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Mibu, Tochigi, Japan
| | - John A. Sayer
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, United Kingdom
- * E-mail:
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20
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Kim YH, Cho JT. A case of exercise-induced acute renal failure with G774A mutation in SCL22A12 causing renal hypouricemia. J Korean Med Sci 2011; 26:1238-40. [PMID: 21935282 PMCID: PMC3172664 DOI: 10.3346/jkms.2011.26.9.1238] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/01/2011] [Indexed: 02/04/2023] Open
Abstract
Acute renal failure with severe loin pain which develops after anaerobic exercise is rare. One of predisposing factors of exercise-induced acute renal failure is renal hypouricemia. Idiopathic renal hypouricemia is a genetic disorder characterized by hypouricemia with abnormally high renal tubular uric acid excretion. The mutation in SCL22A12 gene which encodes renal uric acid transporter, URAT1, is the known major cause of this disorder. We here described a 25-yr-old man showing idiopathic renal hypouricemia with G774A mutation in SCL22A12 who presented exercise-induced acute renal failure. There have been a few reports of mutational analysis in Korean idiopathic renal hypouricemia without acute renal failure. This is the first report of genetically diagnosed idiopathic renal hypouricemia with exercise-induced acute renal failure in Korea.
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Affiliation(s)
- Yong Hyun Kim
- Department of Internal Medicine, College of Medicine, Dankook University, Cheonan, Korea
| | - Jong Tae Cho
- Department of Internal Medicine, College of Medicine, Dankook University, Cheonan, Korea
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21
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Aida Y, Shibata Y, Osaka D, Abe S, Inoue S, Fukuzaki K, Tokairin Y, Igarashi A, Yamauchi K, Nemoto T, Nunomiya K, Kishi H, Sato M, Watanabe T, Konta T, Kawata S, Kato T, Kubota I. The relationship between serum uric acid and spirometric values in participants in a health check: the Takahata study. Int J Med Sci 2011; 8:470-8. [PMID: 21850198 PMCID: PMC3156995 DOI: 10.7150/ijms.8.470] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 07/25/2011] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Tissue hypoxia induces the degradation of adenosine triphosphate, resulting in the production of uric acid (UA). Patients with chronic obstructive pulmonary disease (COPD) have been reported to have high serum levels of UA (sUA), compared with control subjects. However, the relationship between sUA levels and spirometric measures has not been investigated in detail in a general population. METHODS Subjects aged 40 years or older (n = 2,917), who had participated in a community-based annual health check in Takahata, Japan, in 2004 and 2005, were enrolled in the study. These subjects performed spirometry, their blood pressure was measured, and a blood sample was taken. RESULTS sUA levels were significantly higher in males than in females. Percent predicted forced vital capacity [FVC %predicted] (r = -0.13) and forced expiratory volume in 1 s [FEV(1) %predicted] (r = -0.118) were inversely correlated with sUA levels in females but not in males. Univariate regression analysis indicated that age, body mass index (BMI), ethanol intake, mean blood pressure (BP), and serum creatinine (sCr) were significantly associated with sUA levels in males. In females, age, BMI, mean BP, hemoglobin A1c, sCr, FVC %predicted, and FEV(1) %predicted were significantly associated with sUA levels. Multiple linear regression analysis showed that for both genders, FVC %predicted and FEV(1) %predicted were predictive for sUA levels, independently of the other clinical parameters. Subjects with lung restriction had higher sUA levels than subjects without lung restriction. In addition, subjects with moderate and severe airflow limitation had higher sUA levels than subjects without airflow limitation or those with mild airflow limitation. CONCLUSION FVC %predicted and FEV(1) %predicted were significantly associated with sUA levels in a general population.
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Affiliation(s)
- Yasuko Aida
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Yoko Shibata
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Daisuke Osaka
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Shuichi Abe
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Sumito Inoue
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Koji Fukuzaki
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Yoshikane Tokairin
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Akira Igarashi
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Keiko Yamauchi
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Takako Nemoto
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Keiko Nunomiya
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Hiroyuki Kishi
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Masamichi Sato
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Tetsu Watanabe
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Tsuneo Konta
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
| | - Sumio Kawata
- 2. Department of Gastroenterology, Yamagata University Hospital, Yamagata, Japan
| | - Takeo Kato
- 3. Department of Neurology, Hematology, Metabolism, Endocrinology, and Diabetology, Yamagata University School of Medicine, Yamagata, Japan
| | - Isao Kubota
- 1. Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan
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Tin A, Woodward OM, Kao WHL, Liu CT, Lu X, Nalls MA, Shriner D, Semmo M, Akylbekova EL, Wyatt SB, Hwang SJ, Yang Q, Zonderman AB, Adeyemo AA, Palmer C, Meng Y, Reilly M, Shlipak MG, Siscovick D, Evans MK, Rotimi CN, Flessner MF, Köttgen M, Cupples LA, Fox CS, Köttgen A. Genome-wide association study for serum urate concentrations and gout among African Americans identifies genomic risk loci and a novel URAT1 loss-of-function allele. Hum Mol Genet 2011; 20:4056-68. [PMID: 21768215 DOI: 10.1093/hmg/ddr307] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Serum urate concentrations are highly heritable and elevated serum urate is a key risk factor for gout. Genome-wide association studies (GWAS) of serum urate in African American (AA) populations are lacking. We conducted a meta-analysis of GWAS of serum urate levels and gout among 5820 AA and a large candidate gene study among 6890 AA and 21 708 participants of European ancestry (EA) within the Candidate Gene Association Resource Consortium. Findings were tested for replication among 1996 independent AA individuals, and evaluated for their association among 28 283 EA participants of the CHARGE Consortium. Functional studies were conducted using (14)C-urate transport assays in mammalian Chinese hamster ovary cells. In the discovery GWAS of serum urate, three loci achieved genome-wide significance (P< 5.0 × 10(-8)): a novel locus near SGK1/SLC2A12 on chromosome 6 (rs9321453, P= 1.0 × 10(-9)), and two loci previously identified in EA participants, SLC2A9 (P= 3.8 × 10(-32)) and SLC22A12 (P= 2.1 × 10(-10)). A novel rare non-synonymous variant of large effect size in SLC22A12, rs12800450 (minor allele frequency 0.01, G65W), was identified and replicated (beta -1.19 mg/dl, P= 2.7 × 10(-16)). (14)C-urate transport assays showed reduced urate transport for the G65W URAT1 mutant. Finally, in analyses of 11 loci previously associated with serum urate in EA individuals, 10 of 11 lead single-nucleotide polymorphisms showed direction-consistent association with urate among AA. In summary, we identified and replicated one novel locus in association with serum urate levels and experimentally characterize the novel G65W variant in URAT1 as a functional allele. Our data support the importance of multi-ethnic GWAS in the identification of novel risk loci as well as functional variants.
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Affiliation(s)
- Adrienne Tin
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA
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Shima Y, Nozu K, Nozu Y, Togawa H, Kaito H, Matsuo M, Iijima K, Nakanishi K, Yoshikawa N. Recurrent EIARF and PRES with severe renal hypouricemia by compound heterozygous SLC2A9 mutation. Pediatrics 2011; 127:e1621-5. [PMID: 21536615 DOI: 10.1542/peds.2010-2592] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Renal hypouricemia (RHU) is a hereditary disease that predisposes affected people to exercise-induced acute renal failure (EIARF). In most patients with RHU, the disorder is caused by loss-of-function mutations in SLC22A12 (solute carrier family 22, member 12), which encodes urate transporter 1 (URAT1). Patients with RHU without any mutations in the URAT1 gene were recently found to have a mutation in the glucose transporter 9 (GLUT9) gene (SLC2A9 [solute carrier family 2, member 9]). Central nervous system complications seem to be rare in patients with RHU with SLC22A12 mutations. Here, we report the case of a girl with severe RHU (serum urate: 5.9 μmol/L [0.1 mg/dL]) associated with recurrent EIARF in whom the disease was caused by a compound heterozygous mutation in SLC2A9, a nonsense mutation in the paternal allele (p.G207X in exon 7), and a large duplication (c.1-2981_1204+16502) in the maternal allele detected by reverse-transcription polymerase chain reaction (PCR), semiquantitative PCR, long PCR, and direct sequencing. The episodes of EIARF were complicated by posterior reversible encephalopathy syndrome (PRES), which suggested a relationship between PRES and GLUT9 or severe hypouricemia. This is the second report of mutations of both alleles of SLC2A9 that resulted in severe hypouricemia. Our findings indicate that even a nonsense mutation responsible for the heterozygous status of SLC2A9 did not cause severe hypouricemia, and they lend support to previous speculation that mutations of both SLC2A9 alleles cause severe hypouricemia. Our case shows that GLUT9, unlike URAT1, may play a specific role in exercise-induced PRES.
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Affiliation(s)
- Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama City, Wakayama, 641-8509, Japan
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24
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Cause of uric acid stones in rotavirus-associated gastroenteritis. Pediatr Nephrol 2010; 25:2187-8. [PMID: 20191366 DOI: 10.1007/s00467-010-1490-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 02/02/2010] [Accepted: 02/02/2010] [Indexed: 10/19/2022]
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The case: a young man with acute kidney injury after exercise. The diagnosis: exercise induced acute kidney injury in hereditary renal hypouricemia. Kidney Int 2010; 77:935-6. [PMID: 20431587 DOI: 10.1038/ki.2009.563] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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26
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Guan M, Zhang J, Chen Y, Liu W, Kong N, Zou H. High-resolution melting analysis for the rapid detection of an intronic single nucleotide polymorphism in SLC22A12 in male patients with primary gout in China. Scand J Rheumatol 2010; 38:276-81. [PMID: 19306160 DOI: 10.1080/03009740802572483] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The human urate transporter 1 (URAT1, encoded by SLC22A12) was recently identified as the major absorptive urate transporter protein in the kidney responsible for regulating blood urate levels. The present study was designed to investigate the rs893006 polymorphism (GG, GT, and TT) in SLC22A12 in a total of 292 Chinese male subjects. Differences of clinical characteristics among the genotype groups were analysed. METHODS A total of 124 consecutive patients with diagnosis of primary gout and 168 healthy male volunteers were enrolled in this study. Demographic and clinical data were obtained from the patients and controls. DNA was purified from peripheral blood and the rs893006 polymorphism was determined with sequencing analysis. In addition, DNA samples were detected by high-resolution melting (HRM) analysis. Melting curves were analysed as fluorescence difference plots. The shift and curve shapes of melting profiles were used to distinguish the different genotypes. RESULTS GG, GT, and TT genotypes were unambiguously distinguished with HRM technology. Genotyping based on HRM analysis was fully concordant with the sequencing. Serum uric acid levels in the TT genotype subjects were significantly lower than those in the GG and GT genotypes. However, no differences among the groups were found in body mass index (BMI), blood pressure, creatinine, total cholesterol, and triglycerides. The TT genotype was observed more frequently among the low uric acid group than the high uric acid group. CONCLUSIONS HRM analysis is a simple, rapid and accurate one-tube assay for genotyping the SLCSSA12 gene. The rs893006 polymorphism in SLC22CA12 was confirmed to be a genetic risk for hyperuricaemia among the Chinese male population.
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Affiliation(s)
- M Guan
- Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P. R. China
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27
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Ouellet G, Lin SH, Nolin L, Bonnardeaux A. [Hereditary renal hypouricemia in a Caucasian patient: a case report and review of the literature]. Nephrol Ther 2009; 5:568-71. [PMID: 19464979 DOI: 10.1016/j.nephro.2009.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 03/18/2009] [Accepted: 03/18/2009] [Indexed: 11/25/2022]
Abstract
Hereditary renal hypouricemia is characterized by a decreased serum uric acid, a uric acid fractional excretion above normal and the absence of another cause of hyperuricosuric hypouricemia. This pathology, generally caused by a mutation of urate renal transporter URAT1, is relatively common in Asia, but occurs very infrequently in Caucasian populations. The disease's association with exercise-induced acute renal failure is well known. This article reports the case of a 47-year-old man of Italian origin who was diagnosed with hereditary renal hypouricemia after an episode of exercise-induced acute renal failure. Molecular analysis of SLC22A12 encoding URAT1 for renal hypouricemia using peripheral blood genomic DNA of the patient was performed. Single-strand conformation polymorphism screening, amplification, and direct sequencing of SLC22A12 revealed no mutation in this patient. This suggests that another gene can be involved in this disease.
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Affiliation(s)
- Georges Ouellet
- Service de néphrologie, hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada
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Non-urate transporter 1-related renal hypouricemia and acute renal failure in an Israeli-Arab family. Pediatr Nephrol 2009; 24:999-1003. [PMID: 19189137 DOI: 10.1007/s00467-008-1093-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 11/23/2008] [Accepted: 12/01/2008] [Indexed: 02/04/2023]
Abstract
Idiopathic renal hypouricemia (IRHU) is a rare hereditary disease, predisposing the individual to exercise-induced acute renal failure (EIARF) and nephrolithiasis, and it is characterized by increased clearance of renal uric acid. Most of the described patients are Japanese, who have loss-of-function mutations in the SLC22A12 gene coding for the human urate transporter 1 (URAT1) gene. An 18-year-old youth, who was admitted for EIARF due to IRHU, and six consanguineous Israeli-Arab family members were included in the study. The family members were tested for fractional excretion of uric acid and molecular analysis of the URAT1 gene. Four family members, including the proband, had very low levels of blood uric acid and high rate of fractional excretion (FE urate> 100%) of uric acid. Genetic analysis of the affected family members did not reveal a mutation in the coding regions and intron-exon boundaries of SCL22A12. Haplotype analysis excluded SCL22A12 involvement in the pathogenesis, suggesting a different gene as a cause of the disease. We herein describe the first Israeli-Arab family with IRHU. A non-URAT1 genetic defect that causes decreased reabsorption or, more probably, increased secretion of uric acid, induces IRHU. Further studies are required in order to elucidate the genetic defect.
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Kaneko K, Taniguchi N, Tanabe Y, Nakano T, Hasui M, Nozu K. Oxidative imbalance in idiopathic renal hypouricemia. Pediatr Nephrol 2009; 24:869-71. [PMID: 18936980 DOI: 10.1007/s00467-008-1032-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 09/25/2008] [Accepted: 09/25/2008] [Indexed: 02/04/2023]
Abstract
An important complication of idiopathic renal hypouricemia is exercise-induced acute renal failure (ARF). The most plausible explanation for this complication is that decreased antioxidant potential leads to kidney injury by reactive oxygen species (ROS). We demonstrated this oxidative imbalance by a concomitant assessment of ROS production and antioxidant system capability in a 15- year-old girl with idiopathic renal hypouricemia caused by a mutation in the urate transporter (URAT1) gene. Her serum level of ROS increased with decreasing antioxidant potential capacity soon after the initiation of anaerobic stress due to treadmill exercise. Thereafter, serum levels of ROS and antioxidant potential showed a parallel course, returning to the baseline values at 240 min after exercise. Some patients with idiopathic renal hypouricemia demonstrate oxidative imbalance soon after exercise with a predisposition to exercise-induced acute renal failure. Antioxidant properties may alter this imbalance by augmenting the antioxidant activity.
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Affiliation(s)
- Kazunari Kaneko
- Department of Pediatrics, Kansai Medical University, 2-3-1 Shin-machi, Hirakata-shi, Osaka 573-1191, Japan.
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Bannasch D, Safra N, Young A, Karmi N, Schaible RS, Ling GV. Mutations in the SLC2A9 gene cause hyperuricosuria and hyperuricemia in the dog. PLoS Genet 2008; 4:e1000246. [PMID: 18989453 PMCID: PMC2573870 DOI: 10.1371/journal.pgen.1000246] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 09/30/2008] [Indexed: 01/23/2023] Open
Abstract
Allantoin is the end product of purine catabolism in all mammals except humans, great apes, and one breed of dog, the Dalmatian. Humans and Dalmatian dogs produce uric acid during purine degradation, which leads to elevated levels of uric acid in blood and urine and can result in significant diseases in both species. The defect in Dalmatians results from inefficient transport of uric acid in both the liver and renal proximal tubules. Hyperuricosuria and hyperuricemia (huu) is a simple autosomal recessive trait for which all Dalmatian dogs are homozygous. Therefore, in order to map the locus, an interbreed backcross was used. Linkage mapping localized the huu trait to CFA03, which excluded the obvious urate transporter 1 gene, SLC22A12. Positional cloning placed the locus in a minimal interval of 2.5 Mb with a LOD score of 17.45. A critical interval of 333 kb containing only four genes was homozygous in all Dalmatians. Sequence and expression analyses of the SLC2A9 gene indicated three possible mutations, a missense mutation (G616T;C188F) and two promoter mutations that together appear to reduce the expression levels of one of the isoforms. The missense mutation is associated with hyperuricosuria in the Dalmatian, while the promoter SNPs occur in other unaffected breeds of dog. Verification of the causative nature of these changes was obtained when hyperuricosuric dogs from several other breeds were found to possess the same combination of mutations as found in the Dalmatian. The Dalmatian dog model of hyperuricosuria and hyperuricemia underscores the importance of SLC2A9 for uric acid transport in mammals.
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Affiliation(s)
- Danika Bannasch
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
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Endou H, Anzai N. Urate transport across the apical membrane of renal proximal tubules. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2008; 27:578-84. [PMID: 18600508 DOI: 10.1080/15257770802136024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Since the molecular cloning of the renal apical urate/anion exchanger URAT1 (SLC22A12), several membrane proteins relevant to urate transport have been identified. In addition, the identification of PDZ (PSD-95, DglA, and ZO-1) domain protein PDZK1 as a binding partner of URAT1, and the emerging role of PDZ scaffold for renal apical transporters have led to a new concept of renal urate transport: urate-transporting multimolecular complex, or "urate transportsome," that may form an ultimate functional unit at the apical membrane of renal proximal tubules. Elucidation of urate transportsome will lead to the new drug development for hyperuricemia.
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Affiliation(s)
- Hitoshi Endou
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Tokyo, Japan.
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Eraly SA, Vallon V, Rieg T, Gangoiti JA, Wikoff WR, Siuzdak G, Barshop BA, Nigam SK. Multiple organic anion transporters contribute to net renal excretion of uric acid. Physiol Genomics 2008; 33:180-92. [PMID: 18270321 DOI: 10.1152/physiolgenomics.00207.2007] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Excretion of uric acid, a compound of considerable medical importance, is largely determined by the balance between renal secretion and reabsorption. The latter process has been suggested to be principally mediated by urate transporter 1 (URAT1; slc22a12), but the role of various putative urate transporters has been much debated. We have characterized urate handling in mice null for RST, the murine ortholog of URAT1, as well as in those null for the related organic anion transporters Oat1 and Oat3. Expression of mRNA of other putative urate transporters (UAT, MRP2, MRP4, Oatv1) was unaffected in the knockouts, as were general indexes of renal function (glomerular filtration rate, fractional excretion of fluid and electrolytes). While mass spectrometric analyses of urine and plasma revealed significantly diminished renal reabsorption of urate in RST-null mice, the bulk of reabsorption, surprisingly, was preserved. Oat1- and Oat3-null mice manifested decreased secretion rather than reabsorption, indicating that these related transporters transport urate in the "opposite" direction to RST. Moreover, metabolomic analyses revealed significant alteration in the concentration of several molecules in the plasma and urine of RST knockouts, some of which may represent additional substrates of RST. The results suggest that RST, Oat1, and Oat3 each contribute to urate handling, but, at least in mice, the bulk of reabsorption is mediated by a transporter(s) that remains to be identified. We discuss the data in the context of recent human genetic studies that suggest that the magnitude of the contribution of URAT1 to urate reabsorption might vary with ethnic background.
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Affiliation(s)
- Satish A Eraly
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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Abstract
Uric acid nephrolithiasis may be the final manifestation of various pathophysiological processes. Recent advances in renal urate transport have elucidated mechanisms by which hyperuricosuria occurs. However, in most uric acid stone formers the primary pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Insulin resistance may contribute to the development of acidic urine by augmenting endogenous acid production and decreasing renal ammonium excretion. Medical management strategies focus primarily on alkali treatment or decreasing hyperuricosuria.
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Affiliation(s)
- Mary Ann Cameron
- The Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8885, USA.
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Ohtsuka Y, Zaitsu M, Ichida K, Isomura N, Tsuji K, Sato T, Hamasaki Y. Human uric acid transporter 1 gene analysis in familial renal hypo-uricemia associated with exercise-induced acute renal failure. Pediatr Int 2007; 49:235-7. [PMID: 17445045 DOI: 10.1111/j.1442-200x.2007.02337.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yasufumi Ohtsuka
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
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Rizwan AN, Burckhardt G. Organic anion transporters of the SLC22 family: biopharmaceutical, physiological, and pathological roles. Pharm Res 2007; 24:450-70. [PMID: 17245646 DOI: 10.1007/s11095-006-9181-4] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 10/19/2006] [Indexed: 02/08/2023]
Abstract
The human organic anion transporters OAT1, OAT2, OAT3, OAT4 and URAT1 belong to a family of poly-specific transporters mainly located in kidneys. Selected OATs occur also in liver, placenta, and brain. OATs interact with endogenous metabolic end products such as urate and acidic neutrotransmitter metabolites, as well as with a multitude of widely used drugs, including antibiotics, antihypertensives, antivirals, anti-inflammatory drugs, diuretics and uricosurics. Thereby, OATs play an important role in renal drug elimination and have an impact on pharmacokinetics. In this review we focus on the interaction of human OATs with drugs. We report the affinities of human OATs for drug classes and compare the putative importance of individual OATs for renal drug excretion. The role of OATs as sites of drug-drug interaction and mediators cell toxicity, their gender-dependent regulation in health and diseased states, and the possible impact of single nucleotide polymorphisms are also dealt with.
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Affiliation(s)
- Ahsan N Rizwan
- Abteilung Vegetative Physiologie und Pathophysiologie, Bereich Humanmedizin, Georg-August-Universität Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
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Abstract
PURPOSE OF REVIEW This review focuses on recent progress in the understanding of various aspects of renal transport of urate. RECENT FINDINGS Since the molecular cloning of the renal apical urate/anion exchanger URAT1 (SLC22A12), several membrane proteins relevant to the transport of urate have been identified. The molecular identification of two sodium-coupled monocarboxylate transporters, SMCT1(SLC5A8) and SMCT2(SLC5A12), and the emerging role of PDZ (PSD-95, DglA, and ZO-1) scaffold for renal apical transporters have led to a new concept of renal urate transport: urate-transporting multimolecular complex, or 'urate transportsome', that may form an ultimate functional unit including the sodium-coupled urate transport system by linking URAT1 and sodium-coupled monocarboxylate transporters or the coordinated apical urate uptake system by balancing reabsorptive (URAT1) and efflux (NPT1/OATv1 and MRP4) transporters. In addition, genetic variations of the URAT1 gene are associated not only with idiopathic renal hypouricemia but also with reduced renal urate excretion. SUMMARY Although our knowledge of renal urate handling has been increased by the molecular identification of urate transport proteins and by results of genetic studies on patients with serum urate disorders, current evidence is insufficient to fully understand the precise mechanism governing the bi-directional transport of urate. Further studies are still necessary.
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Affiliation(s)
- Naohiko Anzai
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Shinkawa, Mitaka-shi, Tokyo, Japan
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Han MH, Park SU, Kim DS, Shim JW, Shim JY, Jung HL, Park MS. A case of idiopathic renal hypouricemia. KOREAN JOURNAL OF PEDIATRICS 2007. [DOI: 10.3345/kjp.2007.50.5.489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Moon Hee Han
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sang Uk Park
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Deok-Soo Kim
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jae Won Shim
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jung Yeon Shim
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Lym Jung
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Moon Soo Park
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
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Komatsuda A, Iwamoto K, Wakui H, Sawada KI, Yamaguchi A. Analysis of mutations in the urate transporter 1 (URAT1) gene of Japanese patients with hypouricemia in northern Japan and review of the literature. Ren Fail 2006; 28:223-7. [PMID: 16703794 DOI: 10.1080/08860220600580365] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
BACKGROUND Renal hypouricemia is an autosomal recessive disorder resulting from inactivating mutations in the urate transporter 1 (URAT1) encoded by SLC22A12. To date, 10 mutations have been identified and W258X in the URAT1 gene is the predominant cause in middle to southwestern Japan. However, it is still unclear whether there is a regional specific distribution of mutations in northern Japan. In this study, we analyzed mutations in the URAT1 gene of five Japanese patients with renal hypouricemia in northern Japan. METHODS Peripheral blood mononuclear cells were isolated from patients with hypouricemia and healthy control subjects. A mutation analysis of the URAT1 gene was performed completely by direct automated sequencing of polymerase chain reaction-amplified DNA products. RESULTS We identified two mutations. These mutations [c.269G>A (R90H) and c.774G>A (W258X)] have been reported in Japanese patients. Two of five patients were homozygotes (W258X), two carried single heterozygous mutations (W258X), and the remaining one was a compound heterozygote (R90H and W258X). CONCLUSIONS Our study suggests that there is no regional different distribution of the URAT1 genetic mutations in Japanese with renal hypouricemia.
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Affiliation(s)
- Atsushi Komatsuda
- Third Department of Internal Medicine, Akita University School of Medicine, Japan.
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Murthy R, Chahal M, Appel G, Bergmann S, Tikofsky R, Fawwaz R, Van Heertum R. Exercise acutely increases renal transit time of Tc-99m mercaptoacetyltriglycine (MAG3) in a post-liver transplant patient. Clin Nucl Med 2006; 31:829-34. [PMID: 17117088 DOI: 10.1097/01.rlu.0000247736.14647.ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This case demonstrates the effect of exercise on the clearance of Tc-99m MAG3 in a patient with renal insufficiency status post-liver transplant. Even after furosemide administration, the tracer was retained in the kidneys after exercise. This is in contrast to normal clearance demonstrated on a baseline study performed 3 days previously.
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Affiliation(s)
- Rajan Murthy
- Department of Radiology, New York-Presbyterian Hospital Columbia-Presbyterian Medical Center, New York, NY 10032, USA.
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Abstract
The prevalence of gout appears to be rapidly increasing worldwide and is no longer a disorder suffered primarily by over-fed alcohol consumers. Emerging risk factors include longevity, metabolic syndrome, and new classes of pharmacologic agents. In some ethnic populations, no obvious risk factors can explain the high incidence of hyperuricemia and gout, suggesting a genetic liability. Studies to identify genes associated with gout have included families with defects in purine metabolism, as well as families in whom the occurrence of gout is secondary to renal disorders such as juvenile hyperuricemic nephropathy and medullary cystic kidney disease. Case-control studies of isolated aboriginal cohorts suffering from primary gout have revealed several chromosomal loci that may harbor genes that are important to the development and/or progression of gout.
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Enomoto A, Endou H. Roles of organic anion transporters (OATs) and a urate transporter (URAT1) in the pathophysiology of human disease. Clin Exp Nephrol 2005; 9:195-205. [PMID: 16189627 DOI: 10.1007/s10157-005-0368-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 05/13/2005] [Indexed: 12/22/2022]
Abstract
Renal proximal and distal tubules are highly polarized epithelial cells that carry out the specialized directional transport of various solutes. This renal function, which is essential for homeostasis in the body, is achieved through the close pairing of apical and basolateral carriers expressed in the renal epithelial cells. The family of organic anion transporters (OATs), which belong to the major facilitator superfamily (SLC22A), are expressed in the renal epithelial cells to regulate the excretion and reabsorption of endogenous and exogenous organic anions. We now understand that these OATs are crucial components in the renal handling of drugs and their metabolites, and they are implicated in various clinically important drug interactions, and their adverse reactions. In recent years, the molecular entities of these transporters have been identified, and their function and regulatory mechanisms have been partially clarified. Workers in this field have identified URAT1 (urate transporter 1), a novel member of the OAT family that displays unique and selective substrate specificity compared with other multispecific OATs. In the OAT family, URAT1 is the main transporster responsible for human genetic diseases. In this review, we introduce and discuss some novel aspects of OATs, with special emphasis on URAT1, in the context of their biological significance, functional regulation, and roles in human disease.
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Affiliation(s)
- Atsushi Enomoto
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan
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Cheong HI, Kang JH, Lee JH, Ha IS, Kim S, Komoda F, Sekine T, Igarashi T, Choi Y. Mutational analysis of idiopathic renal hypouricemia in Korea. Pediatr Nephrol 2005; 20:886-90. [PMID: 15912381 DOI: 10.1007/s00467-005-1863-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 01/03/2005] [Accepted: 01/05/2005] [Indexed: 02/04/2023]
Abstract
Idiopathic renal hypouricemia is a hereditary disease characterized by abnormally high renal uric acid clearance. Most patients are clinically silent, but acute renal failure (ARF), urolithiasis, or hematuria may develop. A defect in the SLC22A12 gene, which encodes the renal uric acid transporter, URAT1, is the known major cause of this disorder. We performed a mutational analysis of the SLC22A12 gene in five Korean patients with idiopathic renal hypouricemia in this study. Two patients presented with microscopic hematuria, one with uric acid urolithiasis, and one with exercise-induced ARF. One patient was asymptomatic. Three different mutations, W258X, R90H and R477H, were detected in four of the patients. However, no mutation was found in the fifth ARF patient. This is the first study of SLC22A12 mutations in a country other than Japan. W258X was found to be the predominant SLC22A12 mutation in Korean renal hypouricemia patients, as has been reported in Japan.
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Affiliation(s)
- Hae Il Cheong
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.
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Abstract
Urate is the major inert end product of purine degradation in higher primates in contrast to most other mammals because of the genetic silencing of hepatic oxidative enzyme uricase. The kidney plays a dominant role in urate elimination. The kidney excretes 70% of the daily urate production. Therefore, it is important to understand renal urate handling mechanism because the under excretion of urate has been implicated in the development of hyperuricemia that leads to gout. The urate transport systems exist in the proximal tubule but they are complicated because of their bidirectional transport and the species differences. Recently, we have identified the urate-anion exchanger URAT1 (SLC22A12) in the human kidney and found that defects in SLC22A12 lead to idiopathic renal hypouricemia. URAT1 is targeted by uricosuric and antiuricosuric agents that affect urate excretion. Molecular identification of urate transporting proteins will lead to the new drug development for hyperuricemia.
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Affiliation(s)
- Naohiko Anzai
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611, Japan.
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Ishikawa I, Nakagawa M, Hayama S, Yoshida S, Date T. Acute renal failure with severe loin pain and patchy renal ischaemia after anaerobic exercise (ALPE) (exercise-induced acute renal failure) in a father and child with URAT1 mutations beyond the W258X mutation. Nephrol Dial Transplant 2005; 20:1015. [PMID: 15741204 DOI: 10.1093/ndt/gfh751] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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