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Miake J, Hisatome I, Tomita K, Isoyama T, Sugihara S, Kuwabara M, Ogino K, Ninomiya H. Impact of Hyper- and Hypo-Uricemia on Kidney Function. Biomedicines 2023; 11:biomedicines11051258. [PMID: 37238929 DOI: 10.3390/biomedicines11051258] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/28/2023] Open
Abstract
Uric acid (UA) forms monosodium urate (MSU) crystals to exert proinflammatory actions, thus causing gout arthritis, urolithiasis, kidney disease, and cardiovascular disease. UA is also one of the most potent antioxidants that suppresses oxidative stress. Hyper andhypouricemia are caused by genetic mutations or polymorphism. Hyperuricemia increases urinary UA concentration and is frequently associated with urolithiasis, which is augmented by low urinary pH. Renal hypouricemia (RHU) is associated with renal stones by increased level of urinary UA, which correlates with the impaired tubular reabsorption of UA. Hyperuricemia causes gout nephropathy, characterized by renal interstitium and tubular damage because MSU precipitates in the tubules. RHU is also frequently associated with tubular damage with elevated urinary beta2-microglobulin due to increased urinary UA concentration, which is related to impaired tubular UA reabsorption through URAT1. Hyperuricemia could induce renal arteriopathy and reduce renal blood flow, while increasing urinary albumin excretion, which is correlated with plasma xanthine oxidoreductase (XOR) activity. RHU is associated with exercise-induced kidney injury, since low levels of SUA could induce the vasoconstriction of the kidney and the enhanced urinary UA excretion could form intratubular precipitation. A U-shaped association of SUA with organ damage is observed in patients with kidney diseases related to impaired endothelial function. Under hyperuricemia, intracellular UA, MSU crystals, and XOR could reduce NO and activate several proinflammatory signals, impairing endothelial functions. Under hypouricemia, the genetic and pharmacological depletion of UA could impair the NO-dependent and independent endothelial functions, suggesting that RHU and secondary hypouricemia might be a risk factor for the loss of kidney functions. In order to protect kidney functions in hyperuricemic patients, the use of urate lowering agents could be recommended to target SUA below 6 mg/dL. In order to protect the kidney functions in RHU patients, hydration and urinary alkalization may be recommended, and in some cases an XOR inhibitor might be recommended in order to reduce oxidative stress.
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Affiliation(s)
- Junichiro Miake
- Division of Pharmacology, Department of Pathophysiological and Therapeutic Science, Tottori University Faculty of Medicine, Tottori 683-8503, Japan
| | - Ichiro Hisatome
- Department of Cardiology, Yonago Medical Center, Tottori 683-0006, Japan
| | - Katsuyuki Tomita
- Department of Respiratory Disease, Yonago Medical Center, Tottori 683-0006, Japan
| | - Tadahiro Isoyama
- Department of Urology, Yonago Medical Center, Tottori 683-0006, Japan
| | - Shinobu Sugihara
- Health Service Center, Shimane University, Matsue 690-0823, Japan
| | - Masanari Kuwabara
- Intensive Care Unit and Department of Cardiology, Toranomon Hospital, Tokyo 105-8470, Japan
| | - Kazuhide Ogino
- Department of Cardiology, Tottori Red Cross Hospital, Tottori 680-0017, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Tottori University Faculty of Medicine, Tottori 683-8503, Japan
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Miyazaki S, Hamada T, Isoyama T, Okada S, Tomita K, Endo Y, Kuwabara M, Sugihara S, Ogino K, Ninomiya H, Ichida K, Yamamoto K, Takenaka A, Hisatome I. Characterization of Urate Metabolism and Complications of Patients with Renal Hypouricemia. Intern Med 2022. [PMID: 36418091 PMCID: PMC10372278 DOI: 10.2169/internalmedicine.0457-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Both renal hypouricemia (RHU) and gout are associated with renal dysfunction and urolithiasis. The difference in renal complications associated with RHU and gout, however, has not been studied. We characterized the urate metabolism and complications of patients with RHU and compared them with patients with gout. Methods Eighteen patients with RHU who had a serum uric acid (SUA) level <2 mg/dL (10 men and 8 women), 44 patients with gout (44 men) and 16 normouricemic patients (4 men and 12 women) were included. The blood and urinary biochemical data were evaluated. A genetic analysis of uric acid transporter 1 (URAT1) was also conducted in 15 cases with RHU. Results The SUA level of RHU was 0.9±0.5/mg/dl, and the Uur/Ucr and Cur/Ccr were 0.56%±0.14% and 45.7%±18.0%, respectively. A genetic analysis of URAT1 in 15 RHU patients showed that 13 harbored a URAT1 gene mutation, whereas 2 harbored the wild-type gene. The SUA level was significantly lower in RHU patients (n=11) than in either gout patients (n=44) or normouricemic patients (n=16). This reduction was accompanied by the elevation of Cua/Ccr. Urinary beta 2-microglobulin levels were higher in RHU patients than in gout or normouricemia patients. Cua/Ccr correlated with normalized urinary beta 2-microglobulin levels. The prevalence of urolithiasis was 18.2% in RHU cases and 6.8% in gout cases. A homozygous URAT1 mutation was associated with urolithiasis. Conclusion Besides urolithiasis, RHU can be associated with tubular dysfunction, such as elevated urinary beta 2-microglobulin levels.
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Affiliation(s)
| | - Toshihiro Hamada
- Department of Community-Based Family Medicine, Faculty of Medicine, Tottori University, Japan
| | | | | | | | - Yusuke Endo
- Advanced Medicine, Innovation and Clinical Research Center, Tottori University Hospital, Japan
| | | | | | - Kazuhide Ogino
- Department of Cardiology, Tottori Red Cross Hospital, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Faculty of Medicine, Tottori University, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Japan
| | - Kazuhiro Yamamoto
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | | | - Ichiro Hisatome
- Department of Cardiovascular Medicine, Yonago Medical Center, Japan
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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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Nakayama A, Matsuo H, Ohtahara A, Ogino K, Hakoda M, Hamada T, Hosoyamada M, Yamaguchi S, Hisatome I, Ichida K, Shinomiya N. Clinical practice guideline for renal hypouricemia (1st edition). Hum Cell 2019; 32:83-87. [PMID: 30783949 PMCID: PMC6437292 DOI: 10.1007/s13577-019-00239-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 01/17/2019] [Indexed: 11/29/2022]
Abstract
Renal hypouricemia (RHUC) is a disease caused by dysfunction of renal urate reabsorption transporters; however, diagnostic guidance and guidelines for RHUC have been lacking, partly due to the low evidence level of studies on RHUC. This review describes a world-first clinical practice guideline (CPG) and its first version in English for this condition. It was developed following the "MINDS Manual for Guideline Development" methodology, which prioritizes evidence-based medicine. It was published in Japanese in 2017 and later translated into English. The primary goal of this CPG is to clarify the criteria for diagnosing RHUC; another aim is to work towards a consensus on clinical decision-making. One of the CPG's unique points is that it contains textbook descriptions at the expert consensus level, in addition to two clinical questions and recommendations derived from a systematic review of the literature. The guidance shown in this CPG makes it easy to diagnose RHUC from simple blood and urine tests. This CPG contains almost all of the clinical foci of RHUC: epidemiology, pathophysiology, diagnostic guidance, clinical examinations, differential diagnosis, and complications, including exercise-induced acute kidney injury and urolithiasis. A CPG summary as well as a clinical algorithm to assist healthcare providers with a quick reference and notes from an athlete for both physicians and patients are included. We hope that this CPG will help healthcare providers and patients to make clinical decisions, and that it will promote further research on RHUC.
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Affiliation(s)
- Akiyoshi Nakayama
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
- Medical Squadron, Air Base Group, Western Aircraft Control and Warning Wing, Japan Air Self-Defense Force, Kasuga, Japan
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Akira Ohtahara
- Division of Cardiology, Sanin Rosai Hospital, Yonago, Japan
| | - Kazuhide Ogino
- Department of Cardiology, Japanese Red Cross Tottori Hospital, Tottori, Japan
| | - Masayuki Hakoda
- Department of Nutritional Sciences, Faculty of Human Ecology, Yasuda Women's University, Hiroshima, Japan
| | - Toshihiro Hamada
- Department of Regional Medicine, Tottori University Faculty of Medicine, Tottori, Japan
| | - Makoto Hosoyamada
- Department of Human Physiology and Pathology, Faculty Pharma-Science, Teikyo University, Tokyo, Japan
| | - Satoshi Yamaguchi
- Department of Urology, The Urinary Stone Medical Center, Kitasaito Hospital, Asahikawa, Japan
| | - Ichiro Hisatome
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, Tottori, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Nariyoshi Shinomiya
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan.
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Hamada T, Ichida K, Hosoyamada M, Mizuta E, Yanagihara K, Sonoyama K, Sugihara S, Igawa O, Hosoya T, Ohtahara A, Shigamasa C, Yamamoto Y, Ninomiya H, Hisatome I. Uricosuric action of losartan via the inhibition of urate transporter 1 (URAT 1) in hypertensive patients. Am J Hypertens 2008; 21:1157-62. [PMID: 18670416 DOI: 10.1038/ajh.2008.245] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The angiotensin receptor blocker losartan inhibited urate transporter 1 (URAT1) according to in vitro experiments. However, it is still unknown whether the inhibitory effect of losartan on URAT1 contributes to its uricosuric action in humans. METHODS Thirty-two patients with hypertension and nine patients with idiopathic renal hypouricemia (five with and four without hypertension) were enrolled for this study. Hypertensive patients were prescribed oral losartan (50 mg/day, n = 16) or candesartan (8 mg/day, n = 16). Before and after 1-month treatment, the serum concentration of urate (Sur) and creatinine (Scr), and the clearance value of urate (Cur) and creatinine (Ccr) were determined. Clearance studies using the URAT1 inhibitor benzbromarone (100 mg/day) or losartan (50 mg/day) loading test were also performed in these patients. RESULTS Blood pressure (BP) significantly decreased in the patients treated with either losartan or candesartan. Losartan significantly reduced Sur, which was associated with a concomitant increase in the Cur/Ccr ratio, whereas candesartan did not alter these parameters. In hypertensive patients with loss-of-function mutation of URAT1, losartan did not alter either Sur or Cur/Ccr, nor did benzbromarone. The lack of effect of URAT1 inhibitors on renal excretion of urate was independent of the renal function of hypouricemic patients. On the other hand, both losartan and benzbromarone increased Cur/Ccr ratio in hypertensive patients harboring the wild URAT1 gene, regardless of the presence of hypouricemia. CONCLUSIONS These findings suggested that losartan inhibited URAT1 and thereby it lowered Sur levels in hypertensive patients.
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