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Shao Z, Xu Y, Zhang X, Zou C, Xie R. Changes in serum uric acid, serum uric acid/serum creatinine ratio, and gamma-glutamyltransferase might predict the efficacy of neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer. Strahlenther Onkol 2024; 200:523-534. [PMID: 37286741 DOI: 10.1007/s00066-023-02096-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 04/23/2023] [Indexed: 06/09/2023]
Abstract
PURPOSE The purpose of this study was to investigate the predictive value of changes in serum uric acid (SUA), the ratio of serum uric acid to serum creatinine (SUA/SCr), and serum gamma-glutamyltransferase (GGT) from before to after therapy in patients with locally advanced rectal cancer (LARC). METHODS Data from 114 LARC patients from January 2016 to December 2021 were included in this retrospective study. All patients received neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME). The change in SUA was calculated as a ratio: (SUA level after nCRT-SUA level before nCRT)/SUA level before nCRT. The change ratios of SUA/SCr and GGT were calculated in the same way. The efficacy of nCRT was evaluated by magnetic resonance (MR) and postoperative pathological response. A nonlinear model was used to evaluate whether the change ratios of SUA, SUA/SCr, and GGT were associated with the efficacy of nCRT. The predictive power of the change ratios of SUA, SUA/SCr, and GGT was assessed by receiver operating characteristic (ROC) curves. Univariate and multivariate Cox regression analyses were employed to measure the associations between disease-free survival (DFS) and other predictive indicators. The Kaplan-Meier method was used to further compare DFS between groups. RESULTS The nonlinear model indicated that the change ratios of SUA, SUA/SCr, and GGT were associated with the efficacy of nCRT. The change ratios of SUA, SUA/SCr, and GGT were used to predict the area under the ROC curve of efficacy for nCRT (0.95, 0.91-0.99), which was better than the prediction by the change ratio of SUA (0.94, 0.89-0.99), SUA/SCr (0.90, 0.84-0.96), or GGT alone (0.86, 0.79-0.93; p < 0.05). The optimal cut-off values of SUA, SUA/SCr, and GGT change were 0.02, 0.01, and 0.04, respectively. The Kaplan-Meier method indicated that patients with SUA, SUA/SCr, or GGT changes greater than the cut-off values had shorter DFS (p < 0.05). CONCLUSION Change ratios of SUA, SUA/SCr, or GGT greater than the cut-off values implied a risk of poor pathological response after nCRT and shorter DFS in LARC patients.
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Affiliation(s)
- Zhenyong Shao
- Department of Radiotherapy, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, China
| | - Yuyan Xu
- Department of Radiotherapy, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, China
| | - Xuebang Zhang
- Department of Radiotherapy, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, China
| | - Changlin Zou
- Department of Radiotherapy, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, China.
| | - Raoying Xie
- Department of Radiotherapy, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, China.
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Zhang WZ. Uric acid en route to gout. Adv Clin Chem 2023; 116:209-275. [PMID: 37852720 DOI: 10.1016/bs.acc.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.
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Affiliation(s)
- Wei-Zheng Zhang
- VIDRL, The Peter Doherty Institute, Melbourne, VIC, Australia.
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Carvalho JF, Shoenfeld Y. Uric acid levels in primary antiphospholipid syndrome. Lupus 2021; 30:2176-2178. [PMID: 34569385 DOI: 10.1177/09612033211045922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Jozélio F Carvalho
- Institute for Health Sciences from Federal University of Bahia, Salvador, BA, Brazil.,I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Russia
| | - Yehuda Shoenfeld
- I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Russia.,Chaim Sheba Medical Center, The Zabludowicz Research Center for Autoimmune Diseases, Tel. Hashomer, Israel.,Ariel University in the Shomron, Israel
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Hyperuricemia, urine uric excretion, and associated complications in thalassemia patients. Ann Hematol 2019; 98:1101-1110. [PMID: 30721337 DOI: 10.1007/s00277-019-03630-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/29/2019] [Indexed: 01/19/2023]
Abstract
Thalassemia patients have a high cell turnover rate due to chronic hemolysis and ineffective erythropoiesis; therefore, hyperuricemia is anticipated. This study aimed to identify the prevalence of hyperuricemia, gout and nephrolithiasis, conditions associated with serum uric acid (SUA), and urine uric acid excretion (UUA) in thalassemia patients. This was a cross-sectional study in patients aged 15 years or older at Chiang Mai University Hospital. All patients had blood and 24-h urine collection test. We enrolled 112 thalassemia patients in which 67.0% were female, 64.3% had beta thalassemia/Hb E, 76.8% were transfusion dependent, and 59.8% were post splenectomy. The median age was 29 (16-58) years. Mean SUA was 6.7 ± 2.0 mg/dl and hyperuricemia (SUA > 6.8 mg/dl) was found in 47 cases (45.2%). Intact spleen (ORs 4.3, 95%CI 1.55-12.50, p = 0.01) and lower FEuric (ORs 2.08, 95%CI 1.35-3.33, p < 0.01) were associated with hyperuricemia significantly. Seven (6.3%) had gouty arthritis and nine (8%) had microscopic hematuria, one case being confirmed nephrolithiasis. The mean UUA excretion was 981.3 ± 335.0 mg/day and UUA hyperexcretion (> 700 mg/24 h) was found in 83.3%. UUA hyperexcretion patients had renal hyperfiltration 46%, glomerular dysfunction 84%, and tubular dysfunction 7.7%. From our study, hyperuricemia was found in approximately 40% of thalassemia patients but gouty arthritis occurred only in few patients (6%). This may be explained by urinary uric hyperexcretion which is found in over 80%. The significant risk factors for hyperuricemia were intact spleen and lower fraction excretion of uric acid.
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Troyanov S, Delmas-Frenette C, Bollée G, Youhanna S, Bruat V, Awadalla P, Devuyst O, Madore F. Clinical, Genetic, and Urinary Factors Associated with Uromodulin Excretion. Clin J Am Soc Nephrol 2015; 11:62-9. [PMID: 26683887 DOI: 10.2215/cjn.04770415] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/24/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVES The urinary excretion of uromodulin is influenced by common variants in the UMOD gene, and it may be related to NaCl retention and hypertension. Levels of uromodulin are also dependent of the renal function, but other determinants remain unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We tested associations between the urinary excretion of uromodulin; medical history and medication; serum and urinary levels of electrolytes, glucose, and uric acid; and the genotype at the UMOD/Protein Disulfide Isomerase-Like, Testis Expressed locus (rs4293393 and rs12446492); 943 participants from the CARTaGENE Cohort, a random sample from the Canadian population of 20,004 individuals, were analyzed. Participants with available genotyping were obtained from a substudy addressing associations between common variants and cardiovascular disease in paired participants with high and low Framingham risk scores and vascular rigidity indexes. RESULTS The population studied was 54±9 years old, with 51% women and eGFR of 9±14 ml/min per 1.73 m(2). Uromodulin excretion was 25 (11-42) mg/g creatinine. Using linear regression, it was independently higher among patients with higher eGFR, the TT genotype of rs4293393, and the TT genotype of rs12446492. The fractional excretions of urate and sodium showed a strong positive correlation with uromodulin, likely linked to the extracellular volume status. The presence of glycosuria and the use of uricosuric drugs, which both increased the fraction excretion of urate, were independently associated with a lower uromodulin excretion, suggesting novel interactions between uric acid and uromodulin excretion. CONCLUSIONS In this large cohort, the excretion of uromodulin correlates with clinical, genetic, and urinary factors. The strongest associations were between uric acid, sodium, and uromodulin excretions and are likely linked to the extracellular volume status.
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Affiliation(s)
- Stéphan Troyanov
- Nephrology Division, Sacré-Coeur Hospital, Montreal, Quebec, Canada;
| | | | - Guillaume Bollée
- Nephrology Division, Hospital Center for the University of Montreal (CHUM), Montreal, Quebec, Canada
| | - Sonia Youhanna
- Institute of Physiology, Zurich Center for Integrative Human Physiology, Zurich, Switzerland
| | - Vanessa Bruat
- Medical and Population Genomics Laboratory, Research Center, Ste-Justine Hospital, Montreal, Quebec, Canada; and Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Philip Awadalla
- Medical and Population Genomics Laboratory, Research Center, Ste-Justine Hospital, Montreal, Quebec, Canada; and Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Olivier Devuyst
- Institute of Physiology, Zurich Center for Integrative Human Physiology, Zurich, Switzerland;
| | - François Madore
- Nephrology Division, Sacré-Coeur Hospital, Montreal, Quebec, Canada
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DuBois BN, Pearson J, Mahmood T, Nguyen D, Thornburg K, Cherala G. Perinatal growth restriction decreases diuretic action of furosemide in adult rats. Eur J Pharmacol 2014; 728:39-47. [PMID: 24508521 DOI: 10.1016/j.ejphar.2014.01.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
Abstract
Perinatal growth restriction programs higher risk for chronic disease during adulthood via morphological and physiological changes in organ systems. Perinatal growth restriction is highly correlated with a decreased nephron number, altered renal function and subsequent hypertension. We hypothesize that such renal maladaptations result in altered pharmacologic patterns for life. Maternal protein restriction during gestation and lactation was used to induce perinatal growth restriction in the current study. The diuretic response of furosemide (2mg/kg single i.p. dose) in perinatally growth restricted rats during adulthood was investigated. Diuresis, natriuresis and renal excretion of furosemide were significantly reduced relative to controls, indicative of decreased efficacy. While a modest 12% decrease in diuresis was observed in males, females experienced 26% reduction. It is important to note that the baseline urine output and natriuresis were similar between treatment groups. The in vitro renal and hepatic metabolism of furosemide, the in vivo urinary excretion of the metabolite, and the expression of renal drug transporters were unaltered. Creatinine clearance was significantly reduced by 15% and 19% in perinatally growth restricted male and female rats, respectively. Further evidence of renal insufficiency was suggested by decreased uric acid clearance. Renal protein expression of sodium-potassium-chloride cotransporter, a pharmacodynamic target, was unaltered. In summary, perinatal growth restriction could permanently imprint pharmacokinetic processes affecting drug response.
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Affiliation(s)
- Barent N DuBois
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Jacob Pearson
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Tahir Mahmood
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Duc Nguyen
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Kent Thornburg
- Center for Developmental Health, Oregon Health & Science University, Portland, OR 97239, USA; Department of Obstetrics & Gynecology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ganesh Cherala
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA; Center for Developmental Health, Oregon Health & Science University, Portland, OR 97239, USA; Department of Obstetrics & Gynecology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
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Yerges-Armstrong LM, Ellero-Simatos S, Georgiades A, Zhu H, Lewis J, Horenstein RB, Beitelshees AL, Dane A, Reijmers T, Hankemeier T, Fiehn O, Shuldiner AR, Kaddurah-Daouk R. Purine pathway implicated in mechanism of resistance to aspirin therapy: pharmacometabolomics-informed pharmacogenomics. Clin Pharmacol Ther 2013; 94:525-32. [PMID: 23839601 PMCID: PMC4001726 DOI: 10.1038/clpt.2013.119] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/20/2013] [Indexed: 11/08/2022]
Abstract
Although aspirin is a well-established antiplatelet agent, the mechanisms of aspirin resistance remain poorly understood. Metabolomics allows for measurement of hundreds of small molecules in biological samples, enabling detailed mapping of pathways involved in drug response. We defined the metabolic signature of aspirin exposure in subjects from the Heredity and Phenotype Intervention Heart Study. Many metabolites, including known aspirin catabolites, changed on exposure to aspirin, and pathway enrichment analysis identified purine metabolism as significantly affected by drug exposure. Furthermore, purines were associated with aspirin response, and poor responders had higher postaspirin adenosine and inosine levels than did good responders (n = 76; both P < 4 × 10(-3)). Using our established "pharmacometabolomics-informed pharmacogenomics" approach, we identified genetic variants in adenosine kinase associated with aspirin response. Combining metabolomics and genomics allowed for more comprehensive interrogation of mechanisms of variation in aspirin response--an important step toward personalized treatment approaches for cardiovascular disease.
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Affiliation(s)
- Laura M. Yerges-Armstrong
- Program in Personalized and Genomic Medicine, Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Sandrine Ellero-Simatos
- Division Analytical Biosciences, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Netherlands Metabolomics Centre, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Anastasia Georgiades
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Hongjie Zhu
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joshua Lewis
- Program in Personalized and Genomic Medicine, Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Richard B. Horenstein
- Program in Personalized and Genomic Medicine, Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Amber L. Beitelshees
- Program in Personalized and Genomic Medicine, Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Adrie Dane
- Division Analytical Biosciences, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Netherlands Metabolomics Centre, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Theo Reijmers
- Division Analytical Biosciences, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Netherlands Metabolomics Centre, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Thomas Hankemeier
- Division Analytical Biosciences, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Netherlands Metabolomics Centre, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Oliver Fiehn
- Genomics Center, University of California, Davis, California, United States of America
| | - Alan R. Shuldiner
- Program in Personalized and Genomic Medicine, Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Rima Kaddurah-Daouk
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC
- Duke Institute for Brain Sciences, Duke University, Durham, NC
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Stamp LK, O'Donnell JL, Frampton C, Drake JM, Zhang M, Chapman PT. Clinically insignificant effect of supplemental vitamin C on serum urate in patients with gout: a pilot randomized controlled trial. ACTA ACUST UNITED AC 2013; 65:1636-42. [PMID: 23681955 DOI: 10.1002/art.37925] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/28/2013] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Studies in human volunteers have shown that vitamin C reduces serum urate (SU) levels. The aim of this study was to determine the effects of vitamin C on SU levels in patients with gout. METHODS Patients with gout and an SU level >0.36 mmoles/liter (6 mg/dl) were recruited. Twenty patients already taking allopurinol were randomized to receive an increase in the dose of allopurinol or to commence taking vitamin C (500 mg/day). Twenty patients who had not been taking allopurinol were randomized to start receiving either allopurinol (up to 100 mg/day) or vitamin C (500 mg/day). Levels of plasma ascorbate, creatinine, and SU were measured on day 0 and week 8. RESULTS There was no significant difference in the baseline SU level or estimated glomerular filtration rate (eGFR) between those who received vitamin C and those who did not (for SU, mean ± SEM 0.50 ± 0.11 mmoles/liter [8.4 ± 1.8 mg/dl] versus 0.50 ± 0.09 mmoles/liter [8.4 ± 1.5 mg/dl]; for eGFR, mean ± SEM 65.5 ± 3.5 ml/minute/1.73 m(2) versus 67.9 ± 4.6 ml/minute/1.73 m(2) ). Among the randomized patients, 30% in the vitamin C group and 25% in the no vitamin C control group were receiving diuretics. In the patients receiving vitamin C, there was a significant increase between day 0 and week 8 in the plasma ascorbate level. The reduction in SU level over 8 weeks was significantly less in those patients receiving vitamin C compared to those who started or increased the dose of allopurinol (mean reduction 0.014 mmoles/liter [0.23 mg/dl] versus 0.118 mmoles/liter [1.9 mg/dl]; P < 0.001). CONCLUSION A modest dosage of vitamin C (500 mg/day) for 8 weeks had no clinically significant urate-lowering effects in patients with gout, despite the fact that plasma ascorbate levels increased. These results differ from previous findings in healthy control subjects with hyperuricemia. The uricosuric effect of modest-dose vitamin C appears to be small in patients with gout, when administered as monotherapy or in combination with allopurinol.
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Affiliation(s)
- Lisa K Stamp
- University of Otago, Christchurch, Christchurch, New Zealand.
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Simão ANC, Lozovoy MAB, Dichi I. The uric acid metabolism pathway as a therapeutic target in hyperuricemia related to metabolic syndrome. Expert Opin Ther Targets 2012; 16:1175-87. [PMID: 23020656 DOI: 10.1517/14728222.2012.723694] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Uric acid (UA) increase is considered an important risk factor for the development of cardiovascular disease (CVD) favoring oxidative stress and endothelial dysfunction and is also involved in metabolic syndrome (MS) pathophysiology. AREAS COVERED Insulin has a physiological action on renal tubules, causing a reduction in UA clearance, what could explain the hyperuricemia found in MS. On the other hand, it was also hypothesized a causal role of UA in fructose-induced MS. Moreover, it has been suggested that higher UA levels predict the development of MS. MS subjects present a redox imbalance and UA participates in this process. UA can contribute to oxidative stress present in MS; however, it has also an important role in the antioxidant defense system. Although UA may have a protective effect due to its antioxidant properties, it is clear that the dominant effect of UA in MS is deleterious. All-cause mortality and CVD have been shown to be increased with higher UA levels. EXPERT OPINION It is extremely important to prescribe drugs which concomitantly decrease hyperuricemia and improve co-morbidities associated with hyperuricemia. Long-term studies to verify the consequences of decreasing UA concentration below current recommendations in asymptomatic patients are needed.
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Affiliation(s)
- Andréa Name Colado Simão
- Department of Pathology, Clinical Analysis and Toxicology, University of Londrina, Londrina, Paraná, Rua Robert Koch n. 60 Bairro Cervejaria, CEP: 86038-440, Brazil
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Juraschek SP, Miller ER, Gelber AC. Effect of oral vitamin C supplementation on serum uric acid: a meta-analysis of randomized controlled trials. Arthritis Care Res (Hoboken) 2011; 63:1295-306. [PMID: 21671418 DOI: 10.1002/acr.20519] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To assess the effect of vitamin C supplementation on serum uric acid (SUA) by pooling the findings from published randomized controlled trials (RCTs). METHODS A total of 2,082 publications identified through systematic search were subjected to the following inclusion criteria: 1) RCTs conducted on human subjects, 2) reported end-trial SUA means and variance, 3) study design with oral vitamin C supplementation and concurrent control groups, and 4) trial duration of at least 1 week. Trials that enrolled children or patients receiving dialysis were excluded. Two investigators independently abstracted trial and participant characteristics. SUA effects were pooled by random-effects models and weighted by inverse variance. RESULTS Thirteen RCTs were identified in the Medline, EMBase, and Cochrane Central Register of Controlled Trials databases. The total number of participants was 556, the median dosage of vitamin C was 500 mg/day, trial size ranged from 8-184 participants, and the median study duration was 30 days. Pretreatment SUA values ranged from 2.9-7.0 mg/dl (Système International d'Unités [SI units]: 172.5-416.4 μmoles/liter). The combined effect of these trials was a significant reduction in SUA of -0.35 mg/dl (95% confidence interval -0.66, -0.03 [P = 0.032]; SI units: -20.8 μmoles/liter). Trial heterogeneity was significant (I(2) = 77%, P < 0.01). Subgroup analyses based on trial characteristics indicated larger reductions in uric acid in trials that were placebo controlled. CONCLUSIONS In aggregate, vitamin C supplementation significantly lowered SUA. Future trials are needed to determine whether vitamin C supplementation can reduce hyperuricemia or prevent incident and recurrent gout.
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Affiliation(s)
- Stephen P Juraschek
- Johns Hopkins University School of Medicine, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21224, USA
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Effect of hypouricaemic and hyperuricaemic drugs on the renal urate efflux transporter, multidrug resistance protein 4. Br J Pharmacol 2008; 155:1066-75. [PMID: 18724382 DOI: 10.1038/bjp.2008.343] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE The xanthine oxidase inhibitors allopurinol and oxypurinol are used to treat hyperuricaemia, whereas loop and thiazide diuretics can cause iatrogenic hyperuricaemia. Some uricosuric drugs and salicylate have a bimodal action on urate renal excretion. The mechanisms of action of these hypo- and hyperuricaemic drugs on the handling of urate in renal tubules have not been fully elucidated. Recently, we identified the multidrug resistance protein (MRP) 4 as a luminal efflux transporter for urate in the proximal tubule. EXPERIMENTAL APPROACH Here, we studied the effect of these drugs on [(14)C]urate transport using human embryonic kidney 293 cells overexpressing human MRP4 and in membrane vesicles isolated from these cells. KEY RESULTS Allopurinol stimulated MRP4-mediated cellular urate efflux and allopurinol and oxypurinol both markedly stimulated urate transport by MRP4 in membrane vesicles. Bumetanide and torasemide had no effect, whereas furosemide, chlorothiazide, hydrochlorothiazide, salicylate, benzbromarone and sulfinpyrazone inhibited urate transport, at concentrations ranging from nanomolar up to millimolar. Probenecid stimulated urate transport at 0.1 microM and inhibited transport at higher concentrations. CONCLUSIONS AND IMPLICATIONS These data suggest that inhibition of MRP4-mediated urate efflux by furosemide and thiazide diuretics could have an important function in their hyperuricaemic mechanisms. Furthermore, stimulation of MRP4-mediated renal urate efflux could be a new mechanism in the hypouricaemic action of allopurinol and oxypurinol. In conclusion, MRP4 may provide a potential target for drugs affecting urate homoeostasis, which needs to be further evaluated in vivo.
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Tsouli SG, Liberopoulos EN, Mikhailidis DP, Athyros VG, Elisaf MS. Elevated serum uric acid levels in metabolic syndrome: an active component or an innocent bystander? Metabolism 2006; 55:1293-301. [PMID: 16979398 DOI: 10.1016/j.metabol.2006.05.013] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Accepted: 05/04/2006] [Indexed: 12/13/2022]
Abstract
Elevated serum uric acid (SUA) levels are commonly seen in patients with the metabolic syndrome (MetS). Several mechanisms, both direct and indirect, connect the increased SUA levels with the established diagnostic criteria of MetS. It is possible that the increased cardiovascular disease risk associated with the MetS is partially attributed to elevated circulating SUA concentration. Several drugs used in the treatment of MetS may alter SUA levels. Thus, lifestyle measures together with the judicious selection of drugs for the treatment of hypertension, dyslipidemia, and insulin resistance associated with MetS may result in a reduction of SUA levels and possibly cardiovascular disease risk. This review summarizes the pathophysiologic association between SUA and MetS and focuses on the prevention of hyperuricemia and its cardiovascular consequences.
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Affiliation(s)
- Sofia G Tsouli
- Department of Internal Medicine, School of Medicine, University of Ioannina, 45110 Ioannina, Greece
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Chen LX, Schumacher HR. Gout: can we create an evidence-based systematic approach to diagnosis and management? Best Pract Res Clin Rheumatol 2006; 20:673-84. [PMID: 16979531 DOI: 10.1016/j.berh.2006.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The management of gout can be subdivided into four phases. Asymptomatic hyperuricaemia represents the basic underlying metabolic abnormality that can lead to gout. Studies are evaluating whether interventions may be indicated in some cases. Diagnostic criteria for gout and acute flares are still not well defined unless urate crystals are found. Acute attacks of gout are treated with anti-inflammatory measures and the agent of choice is often determined by attack stage, severity and comorbidities that may contra-indicate one or more agents. After attacks subside, there are asymptomatic periods during which decisions must be made about when and how to start urate-lowering measures. If hyperuricaemia persists, there is generally persistence of urate crystals in the joint. Anti-inflammatory prophylaxis is needed when urate-lowering therapy is started. Lifestyle measures should be addressed. If chronic tophaceous gout is diagnosed, urate lowering should be started without delay. New agents are under development that may help with difficult cases.
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Affiliation(s)
- Lan X Chen
- University of Pennsylvannia, Penn-Presbyterian Medical Center, Philadelphia, PA 19104-4283, USA
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Abstract
Newer approaches to the treatment of gout have included modifications and further attention to aspects of current therapies, and development of interesting new therapies. Colchicine prophylaxis appears to be needed longer than previously recognized after introduction of a urate-lowering agent. Diet has received attention, though most dietary effects are small. New agents under investigation include pegylated formulations of uricase and a new potent xanthine oxidase inhibitor, febuxostat. Some cardiovascular drugs have been shown to be uricosuric.
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Affiliation(s)
- H Ralph Schumacher
- Division of Rheumatology, Philadelphia Veterans Affairs Medical Center, Philadelphia, PA 19104, USA.
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Mini-Aspirin. J Clin Rheumatol 2002. [DOI: 10.1097/00124743-200212000-00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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