Uric acid: role in cardiovascular disease and effects of losartan

Simultaneous electrochemical determination of uric acid and hypoxanthine at a TiO2/graphene quantum dot-modified electrode

A TiO2/graphene quantum dots composite (TiO2/GQDs) obtained by in situ synthesis of GQDs, derived from coffee grounds, and peroxo titanium complexes was used as electrode modifier in the simultaneous electrochemical determination of uric acid and hypoxanthine. The TiO2/GQDs material was characterized by photoluminescence, X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray mapping. The TiO2/GQDs-GCE exhibits better electrochemical activity for uric acid and hypoxanthine than GQDs/GCE or TiO2/GCE in differential pulse voltammetry (DPV) measurements. Under optimized conditions, the calibration plots were linear in the range from 1.00 to 15.26 μM for both uric acid and hypoxanthine. The limits of detection of this method were 0.58 and 0.68 μM for uric acid and hypoxanthine, respectively. The proposed DPV method was employed to determine uric acid and hypoxanthine in urine samples with acceptable recovery rates.

The combination of high uric acid and high C-reactive protein increased the risk of cardiovascular disease: A 15-year prospective cohort study

BACKGROUND AND AIMS

Uric acid (UA) and C-reactive protein (CRP) may interact synergistically to accelerate the initiation and progression of cardiovascular disease (CVD). This study investigated the effects of a combination of high UA and high CRP on the risks of CVD.

METHODS AND RESULTS

A total of 90,270 participants recruited from the Kailuan study were included, who were divided into four groups according to the presence/absence of hyperuricemia and inflammation. Cox regression was applied to evaluate the hazard ratios (HRs) and 95% confidence intervals (95% CIs) of CVD. C-statistics, net classification index (NRI), and integrated discrimination improvement (IDI) were used to compare the incremental predictive of UA, CRP, and their combined effects on CVD. Mediation analysis was to explore the impact of CRP on the association between UA and CVD. Over a median follow-up of 14.95 years, we identified 11398 incident CVD cases. Compared to the low UA/low CRP group, the high UA/low CRP, low UA/high CRP and high UA/high CRP groups showed progressively higher risks of CVD, HR (95% CI): 1.18(1.10-1.27), 1.27(1.21-1.33) and 1.50 (1.33-1.69), respectively. The incorporation of UA and CRP into the traditional China-PAR model led to improvement in the C-statistic, NRI, and IDI, and was better than incorporation of either UA or CRP alone. Mediation analysis showed that CRP mediated the association between UA and CVD, accounting for 11.57% of the total effects.

CONCLUSIONS

High UA/high CRP is associated with increased risks of CVD. Incorporation of both UA and CRP provided additional value for risk stratification.

Relation Between Serum Uric Acid to Albumin Ratio and Severity of Chronic Coronary Artery Disease

Uric acid (UA) to albumin ratio (UAR) is an emerging marker to predict coronary artery disease (CAD)-related events. There is limited data on the relationship between UAR and the severity of the disease in chronic CAD patients. We aimed to evaluate UAR as an indicator for CAD severity using the Syntax score (SS). We retrospectively enrolled 558 patients with stable angina pectoris and underwent coronary angiography (CAG). Patients were divided into 2 groups, according to CAD severity: low SS (≤22) and intermediate-high SS (>22) groups. UA levels were higher and albumin levels were lower in the intermediate-high SS score group (P < .001). UAR levels were significantly higher in the intermediate-high SS group (P < .001). Also, there was a significant correlation between UAR levels and SS (r = .55, 95% confidence interval (CI): .49-.60, P < .001). In multivariable analysis, UAR >1.34 (Odds ratio, 3.8 [2.3-6.2]; P < .001) was an independent predictor of intermediate-high SS while albumin and UA levels were not. In conclusion, UAR predicted disease burden in chronic CAD patients. It may prove useful as a simple and readily available marker to select patients for further evaluation.

Natural Substances vs. Approved Drugs in the Treatment of Main Cardiovascular Disorders-Is There a Breakthrough?

Cardiovascular diseases (CVDs) are a group of diseases with a very high rate of morbidity and mortality. The clinical presentation of CVDs can vary from asymptomatic to classic symptoms such as chest pain in patients with myocardial infarction. Current therapeutics for CVDs mainly target disease symptoms. The most common CVDs are coronary artery disease, acute myocardial infarction, atrial fibrillation, chronic heart failure, arterial hypertension, and valvular heart disease. In their treatment, conventional therapies and pharmacological therapies are used. However, the use of herbal medicines in the therapy of these diseases has also been reported in the literature, resulting in a need for critical evaluation of advances related to their use. Therefore, we carried out a narrative review of pharmacological and herbal therapeutic effects reported for these diseases. Data for this comprehensive review were obtained from electronic databases such as MedLine, PubMed, Web of Science, Scopus, and Google Scholar. Conventional therapy requires an individual approach to the patients, as when patients do not respond well, this often causes allergic effects or various other unwanted effects. Nowadays, medicinal plants as therapeutics are frequently used in different parts of the world. Preclinical/clinical pharmacology studies have confirmed that some bioactive compounds may have beneficial therapeutic effects in some common CVDs. The natural products analyzed in this review are promising phytochemicals for adjuvant and complementary drug candidates in CVDs pharmacotherapy, and some of them have already been approved by the FDA. There are insufficient clinical studies to compare the effectiveness of natural products compared to approved therapeutics for the treatment of CVDs. Further long-term studies are needed to accelerate the potential of using natural products for these diseases. Despite this undoubted beneficence on CVDs, there are no strong breakthroughs supporting the implementation of natural products in clinical practice. Nevertheless, they are promising agents in the supplementation and co-therapy of CVDs.

Factors for achieving target serum uric acid levels after initiating urate-lowering therapy in patients with gout: results from the ULTRA registry

Achieving target serum uric acid (SUA) levels is important in gout management. Guidelines recommend lowering SUA levels to < 6 mg/dL; however, many patients fail to reach this target, even with uric acid-lowering therapy (ULT). This study investigated clinical characteristics of target SUA achievers among Korean patients with gout. This study used data from the ULTRA registry, a nationwide inception cohort established in September 2021 that enrolls patients with gout who initiate ULT. Demographic, clinical, and laboratory data were collected at baseline; the 6-month follow-up. Patients were divided into two groups: target achievers (SUA level < 6 mg/dL at 6 months) and non-achievers. The mean participant (N = 117) age was 56.1 years, and 88.0% were male. At 6 months, 83 patients (70.9%) reached target SUA levels. Target achievers had better drug adherence (≥ 80%) to ULT (97.6% vs. 76.5%; p < 0.01) than non-achievers. Target non-achievers had a higher percentage of a family history of gout (32.4% vs. 10.8%; p < 0.01) and less antihypertensive agent use (38.2% vs. 59.0%; p = 0.03) than target achievers. Multivariate regression analysis revealed that good adherence to ULT, the absence of a family history of gout, and antihypertensive agent use were key factors associated with achieving target SUA levels at 6 months.

Review on Uric Acid Recognition by MOFs with a Future in Machine Learning

Uric acid (UA) is produced from purine metabolism and serves as a prevalent biomarker for multiple diseases including cancer. Hyperuricemia or hypouricemia can cause multiple dysfunctions throughout the biological processes. Consequently, there is a pressing need for monitoring UA concentration in body fluid. While clinical methods are known, the availability of a point-of-care testing (PoCT) kit remains conspicuously absent. In the case of electrochemical recognition of UA, the oxidation potential of ascorbic acid closely aligns with that of UA and thus it hinders the detection process, which eventually may result in false positive signals. Several chemosensors are known in the field of supramolecular chemistry, and metal-organic frameworks (MOFs) are one of the best-performing contenders due to their robustness, stability, and versatile structures. In this review, we tried to unbox the up-to-date development of UA sensing by MOFs. We delve into the state of UA recognition by MOFs, exploring both electrochemical and fluorometric pathways and drawing comparisons with structurally similar probes like covalent organic frameworks (COFs) to understand/establish the advantages of MOFs specifically in UA sensing. In the absence of a PoCT kit, we have provided the conceptual outlook for designing a PoCT device termed a "Urimeter" via electrochemical operation. For the first time, we have proposed different methods of how UA sensing can be tied up with artificial intelligence and machine learning (AI-ML).

Investigation of the Inhibition Mechanism of Xanthine Oxidoreductase by Oxipurinol: A Computational Study

Xanthine oxidoreductase (XOR) is an enzyme found in various organisms. It converts hypoxanthine to xanthine and urate, which are crucial steps in purine elimination in humans. Elevated uric acid levels can lead to conditions like gout and hyperuricemia. Therefore, there is significant interest in developing drugs that target XOR for treating these conditions and other diseases. Oxipurinol, an analogue of xanthine, is a well-known inhibitor of XOR. Crystallographic studies have revealed that oxipurinol directly binds to the molybdenum cofactor (MoCo) in XOR. However, the precise details of the inhibition mechanism are still unclear, which would be valuable for designing more effective drugs with similar inhibitory functions. In this study, molecular dynamics and quantum mechanics/molecular mechanics calculations are employed to investigate the inhibition mechanism of XOR by oxipurinol. The study examines the structural and dynamic effects of oxipurinol on the pre-catalytic structure of the metabolite-bound system. Our results provide insights on the reaction mechanism catalyzed by the MoCo center in the active site, which aligns well with experimental findings. Furthermore, the results provide insights into the residues surrounding the active site and propose an alternative mechanism for developing alternative covalent inhibitors.

Serum Uric Acid Levels and Recurrence Rate of Ischemic Stroke: A Meta-Analysis

The role of serum uric acid as a factor in the recurrence of ischemic stroke stays unclear. Several studies have examined the relationship between serum uric acid and recurrence of acute ischemic stroke, with various results. Therefore, we carried out a meta-analysis to have a look at the relationship between serum uric acid levels and the potential danger of stroke recurrence in patients with ischemic stroke. Relevant experiments have been recognized via looking out the electronic databases and conference sessions. This present study included a case-control study of the impact of uric acid on the recurrence of ischemic stroke. After the assessment of eligibility, this meta-analysis included four articles in which 2452 patients with ischemic stroke were tested for their level of serum uric acid. The results obtained from this meta-analysis confirmed that improved uric acid concentrations were extensively and independently related to an accelerated and higher risk of recurrent stroke. The pooled OR (95% CI) was 1.80 (1.47, 2.20) (p<0.001). Overall, this meta-analysis shows a relationship between uric acid concentration and stroke recurrence rate. Furthermore, high uric acid levels could enhance the recurrence rate of ischemic stroke.

Highly Sensitive Electrochemical Non-Enzymatic Uric Acid Sensor Based on Cobalt Oxide Puffy Balls-like Nanostructure

Early-stage uric acid (UA) abnormality detection is crucial for a healthy human. With the evolution of nanoscience, metal oxide nanostructure-based sensors have become a potential candidate for health monitoring due to their low-cost, easy-to-handle, and portability. Herein, we demonstrate the synthesis of puffy balls-like cobalt oxide nanostructure using a hydrothermal method and utilize them to modify the working electrode for non-enzymatic electrochemical sensor fabrication. The non-enzymatic electrochemical sensor was utilized for UA determination using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The puffy balls-shaped cobalt oxide nanostructure-modified glassy carbon (GC) electrode exhibited excellent electro-catalytic activity during UA detection. Interestingly, when we compared the sensitivity of non-enzymatic electrochemical UA sensors, the DPV technique resulted in high sensitivity (2158 µA/mM.cm²) compared to the CV technique (sensitivity = 307 µA/mM.cm²). The developed non-enzymatic electrochemical UA sensor showed good selectivity, stability, reproducibility, and applicability in the human serum. Moreover, this study indicates that the puffy balls-shaped cobalt oxide nanostructure can be utilized as electrode material for designing (bio)sensors to detect a specific analyte.

Excess comorbidities in gout: the causal paradigm and pleiotropic approaches to care

Gout is a common hyperuricaemic metabolic condition that leads to painful inflammatory arthritis and a high comorbidity burden, especially cardiometabolic-renal (CMR) conditions, including hypertension, myocardial infarction, stroke, obesity, hyperlipidaemia, type 2 diabetes mellitus and chronic kidney disease. Substantial advances have been made in our understanding of the excess CMR burden in gout, ranging from pathogenesis underlying excess CMR comorbidities, inferring causal relationships from Mendelian randomization studies, and potentially discovering urate crystals in coronary arteries using advanced imaging, to clinical trials and observational studies. Despite many studies finding an independent association between blood urate levels and risk of incident CMR events, Mendelian randomization studies have largely found that serum urate is not causal for CMR end points or intermediate risk factors or outcomes (such as kidney function, adiposity, metabolic syndrome, glycaemic traits or blood lipid concentrations). Although limited, randomized controlled trials to date in adults without gout support this conclusion. If imaging studies suggesting that monosodium urate crystals are deposited in coronary plaques in patients with gout are confirmed, it is possible that these crystals might have a role in the inflammatory pathogenesis of increased cardiovascular risk in patients with gout; removing monosodium urate crystals or blocking the inflammatory pathway could reduce this excess risk. Accordingly, data for CMR outcomes with these urate-lowering or anti-inflammatory therapies in patients with gout are needed. In the meantime, highly pleiotropic CMR and urate-lowering benefits of sodium-glucose cotransporter 2 (SGLT2) inhibitors and key lifestyle measures could play an important role in comorbidity care, in conjunction with effective gout care based on target serum urate concentrations according to the latest guidelines.

Effect of nanocellulose polymorphism on electrochemical analytical performance in hybrid nanocomposites with non-oxidized single-walled carbon nanotubes

Two cellulose nanocrystals/single-walled carbon nanotube (CNC/SW) hybrids, using two cellulose polymorphs, were evaluated as electrochemical transducers: CNC type I (CNC-I/SW) and CNC type II (CNC-II/SW). They were synthesized and fully characterized, and their analytical performance as electrochemical sensors was carefully studied. In comparison with SWCNT-based and screen-printed carbon electrodes, CNC/SW sensors showed superior electroanalytical performance in terms of sensitivity and selectivity, not only in the detection of small metabolites (uric acid, dopamine, and tyrosine) but also in the detection of complex glycoproteins (alpha-1-acid glycoprotein (AGP)). More importantly, CNC-II/SW exhibited 20 times higher sensitivity than CNC-I/SW for AGP determination, yielding a LOD of 7 mg L^-1.These results demonstrate the critical role played by nanocellulose polymorphism in the electrochemical performance of CNC/SW hybrid materials, opening new directions in the electrochemical sensing of these complex molecules. In general, these high-active-surface hybrids smartly exploited the preserved non-oxidized SW conductivity with the high aqueous dispersibility of the CNC, avoiding the use of organic solvents or the incorporation of toxic surfactants during their processing, making the CNC/SW hybrids promising nanomaterials for electrochemical detection following greener approaches.

Association of Uric Acid With Blood Pressure in Hypertension Between Treatment Group and Non-treatment Group

Objective: This study aimed to explore the association between uric acid (UA) and blood pressure (BP) in hypertension treatment and non-treatment groups.

Methods: A cross-sectional study with 6,985 individuals from the National Health and Nutrition Examination Survey (NHANES) was performed. Multiple linear regression analysis was performed to explore the relationship of UA and BP in hypertension between the treatment group (n = 5,983) and the non-treatment group (n = 1,002).

Results: A significantly negative association was discovered in SBP (β, −0.36 [95% CI, −0.71, −0.01]) and DBP (β, −0.47 [95% CI, −0.69, −0.26]) in the hypertension treatment group. In the hypertension non-treatment group, the associations between UA and BP including SBP, DBP were both an inverted U-shape. The inflection point of SBP and DBP was 7 and 7.5 mg/dl, respectively. For SBP, the association was positively significant (β, 3.11 [95% CI, 1.67, 4.56]) before the inflection point of 7 mg/dl. However, after the inflection point of 7 mg/dl, the association was negative (β, −5.44 [95% CI, −8.6, −2.28]). For DBP, the inflection point was 7.5 mg/dl, and the effect size was positive (β, 1.19 [95% CI, 0.37, 2.01]) before the inflection point. However, after it, the effect size was negative (β, −3.24 [95% CI, −5.72, −0.76]).

Conclusion: The association between UA and BP was negative in the hypertension treatment group. In the hypertension non-treatment group, the associations between UA and BP including SBP and DBP were both an inverted U-shape.

Hyperuricemia in Patients With Coronary Artery Disease and Its Association With Disease Severity

The biochemical background of coronary artery disease (CAD) has been intensively explored in the past several decades. Previous clinical investigations have demonstrated the association of non-traditional risk factors, such as hyperuricemia, with CAD. Studies have shown that increased serum uric acid (SUA) was associated with an increased risk of adverse cardiovascular (CV) outcomes in patients with CAD. While the exact pathophysiological mechanisms leading to increased risk are still unknown, it has been postulated that hyperuricemia leads to endothelial dysfunction, oxidative metabolism, and platelet adhesiveness and aggregation, leading to CAD. Moreover, previous studies have shown that hyperuricemia is an independent risk factor for CAD. However, the correlation between high SUA levels and the severity of CAD remains unclear. The purpose of this review was to elucidate the association of hyperuricemia to CAD severity and to determine the effect of urate-lowering therapy (ULT) on CAD. A search of PubMed up to June 24, 2021, was carried out by the reviewers. From the findings, hyperuricemia stands as an independent risk factor for CAD, and CAD patients treated with ULT had improved CV outcomes and reduced mortality. Therefore, while SUA level is valuable in predicting an augmented risk of CAD and anticipating worse outcomes, ULT has promising cardioprotective effects.

Targeting Xanthine Oxidase by Natural Products as a Therapeutic Approach for Mental Disorders

Mental disorders comprise diverse human pathologies, including depression, bipolar affective disorder, schizophrenia, and dementia that affect millions of people around the world. The causes of mental disorders are unclear, but growing evidence suggests that oxidative stress and the purine/adenosine system play a key role in their development and progression. Xanthine oxidase (XO) is a flavoprotein enzyme essential for the catalysis of the oxidative hydroxylation of purines -hypoxanthine and xanthine- to generate uric acid. As a consequence of the oxidative reaction of XO, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide are produced and, further, contribute to the pathogenesis of mental disorders. Altered XO activity has been associated with free radical-mediated neurotoxicity inducing cell damage and inflammation. Diverse studies reported a direct association between an increased activity of XO and diverse mental diseases including depression or schizophrenia. Small-molecule inhibitors, such as the well-known allopurinol, and dietary flavonoids, can modulate the XO activity and subsequent ROS production. In the present work, we review the available literature on XO inhibition by small molecules and their potential therapeutic application in mental disorders. In addition, we discuss the chemistry and molecular mechanism of XO inhibitors, as well as the use of structure-based and computational methods to design specific inhibitors with the capability of modulating XO activity.

Epidemiology of cardiac or orthopedic procedures in gout versus rheumatoid arthritis: a national time-trends study

Aims

To examine the secular trends in the number and rates of in-hospital cardiac and orthopedic procedures in people with gout and rheumatoid arthritis (RA), and the United States (US) general population, from 1998 to 2014.

Methods

We examined the frequency of seven common cardiac and orthopedic procedures in hospitalized people with gout, RA, or the general population using the 1998-2014 US National Inpatient Sample (NIS). Poisson regression evaluated the differences in frequencies in 1998 versus 2014, between gout and RA, and within each cohort.

Results

Both in-hospital cardiac and orthopedic procedures increased in gout and RA with time, in contrast with declining cardiac procedures in the general US population. Cardiac procedures were significantly higher in gout versus RA in 1998 (59% higher) and 2014 (92% higher). The rate of cardiac procedures increased from 36.6 to 82.8 in gout and from 20.1 to 33.1 in RA per 100,000 NIS claims from 1998 to 2014. Orthopedic procedures became more common than cardiac procedures in gout and RA by 2014. In RA, the cardiac-orthopedic procedure volume difference was significant in 1998 and 2014. We noted no significant difference between cardiac versus orthopedic procedures in 1998 in gout, but the difference was significant in 2014. Orthopedic procedures in gout were significantly lower than RA in 1998 (33% lower), but were significantly higher than RA in 2014 (5% higher).

Conclusion

Increasing in-hospital cardiac procedures in gout and RA contrasting with declining general US population rates indicated that optimal management of systemic inflammation and an early diagnosis of gout and RA are needed. The rate of increase in orthopedic procedures exceeded that in cardiac procedures. A much greater volume and rate of increase in common in-hospital cardiac and orthopedic procedures in gout compared to RA indicates that an aggressive approach to treat-to-target in gout is needed to potentially reduce the associated healthcare burden and cost.

Plain language summary

Cardiac and orthopedic procedures rising faster for gout compared to rheumatoid arthritis in the United States We performed a national US study of the most common cardiac versus orthopedic procedures from 1998 to 2014. We found that over time, the number and the rate of cardiac procedures increased in people with gout (2.2-fold higher) or rheumatoid arthritis (1.6-fold higher). This was surprising, since during the same time, we noted a decrease in cardiac procedures in the general U.S. population. The rate of cardiac procedures in gout was 2.5-fold higher than that in rheumatoid arthritis, 82.8 vs. 33.1 per 100,000 NIS claims in 2014. Interestingly, orthopedic procedures were more common than cardiac procedures in both gout and RA in all periods. Also, the difference in the numbers of cardiac vs. orthopedic procedures increased over time in both gout and RA. Gout outpaced rheumatoid arthritis for both the total number and the rate of cardiac or orthopedic procedures over time. Therefore, our study provides an understanding of an increasing procedure burden in gout compared to rheumatoid arthritis, and to the general U.S. people with these conditions.

Silky Co3O4 nanostructures for the selective and sensitive enzyme free sensing of uric acid

In this study, simple, new and functional silky nanostructures of Co₃O₄ are prepared by hydrothermal method. These nanostructures are successfully used for the enzyme free sensing of uric acid in 0.1 M phosphate buffer solution of pH 7.3. Physical characterization experiments were carried out to explore the morphology, composition and crystalline phase of the newly prepared Co₃O₄ nanostructures. Scanning electron microscopy (SEM) shows a silk like morphology and energy dispersive spectroscopy (EDS) revealed the presence of Co and O as the main elements. Powder X-ray diffraction (XRD) demonstrates a cubic crystallography with well resolved diffraction patterns. The electrochemical activity of these silky Co₃O₄ nanostructures was evaluated by cyclic voltammetry (CV) in a 0.1 M phosphate buffer solution at pH 7.3. The high purity and unique morphology of Co₃O₄ shows a highly sensitive and selective response towards the non-enzymatic sensing of uric acid. This uric acid sensor exhibits a linear range of 0.5 mM to 3.5 mM uric acid and a 0.1 mM limit of detection. The anti-interference capability of this uric acid sensor was monitored in the presence of common interfering species. Furthermore, electrochemical impedance spectroscopy confirms a low charge transfer resistance value of 5.11 K Ω cm² for silky Co₃O₄ nanostructures which significantly supported the CV results. The proposed modified electrode is stable, selective and reproducible which confirms its possible practical use. Silky Co₃O₄ nanostructures can be of great importance for diverse electrochemical applications due to their excellent electrochemical activity and large surface area.

Uric Acid and Hypertension: Prognostic Role and Guide for Treatment

The relationship between serum uric acid (SUA) and hypertension has been a subject of increasing interest since the 1870 discovery by Frederick Akbar Mahomed. Several epidemiological studies have shown a strong association between high SUA levels and the presence or the development of hypertension. Genetic analyses have found that xanthine oxidoreductase (XOR) genetic polymorphisms are associated with hypertension. However, genetic studies on urate transporters and Mendelian randomization studies failed to demonstrate a causal relationship between SUA and hypertension. Results from clinical trials on the role of urate-lowering therapy in the management of patients with hypertension are not uniform. Our study sought to analyze the prognostic and therapeutic role of SUA in the hypertensive disease, from uric acid (UA) biology to clinical trials on urate-lowering therapies.

The Relationship between Serum Vitamin C and Uric Acid Levels, Antioxidant Status and Coronary Artery Disease: a Case-Control Study

Coronary artery disease (CAD) is among the main causes of death in adults. Increase of oxidative stress and defects in antioxidant defense play a major role in endothelium performance and are affecting factors in the progress of atherosclerosis. The aim of this study was to measure serum levels of uric acid (UA) and vitamin C as well as the antioxidant status in patients with CAD, and compared them with those in healthy individuals. The present case-control study was performed on 44 cases and 44 controls. Demographic data and anthropometric indices were measured. The Food Frequency Questionnaire (FFQ) and International Physical Activity Questionnaire (IPAQ) were completed. After 12 hours of fasting,10 mL blood was sampled from the participants. Serum levels of UA, vitamin C, Total Antioxidant Capacity (TAC) and Malondialdehyde (MDA) were also measured. The data were finally analyzed by SPSS v22. A significant difference was observed between the groups in terms of UA and vitamin C. However, mean levels of MDA and TAC were not significantly different between groups. The differences between groups in terms of vitamin A, vitamin E, beta-carotene, zinc and selenium intakes were not significant either. A significant difference was detected between the groups in terms of vitamin C intake. Our results suggest that increase in UA and decrease in vitamin C in serum levels can be considered as risk factors for CAD patients. Due to a lack of any significant correlation between TAC and CAD risk in this study, further study with bigger sample size is needed.

Targets and mechanisms of dietary anthocyanins to combat hyperglycemia and hyperuricemia: a comprehensive review

Hyperglycemia and hyperuricemia are both metabolic disorders related to excessive amount of metabolites in blood, which are considered as high risk factors for the development of many chronic diseases. Enzymes, cells, tissues and organs, which are relevant to metabolism and excretion of glucose and UA, are usually regarded to be the targets in treatment of hyperglycemia and hyperuricemia. Several drugs have been commonly applied to combat hyperglycemia and hyperuricemia through various targets but with unignorable side effects. Anthocyanins have become promising alternatives against hyperglycemia and hyperuricemia because of their bio-activities with little side effects. Structurally different anthocyanins from berry fruits, cherries and purple sweet potato lead to the diverse functional activity and property. This review is aimed to illustrate the specific targets that are available for anthocyanins from berry fruits, cherries and purple sweet potato in hyperglycemia and hyperuricemia management, as well as discuss the structure-activity relationship, and the underlying mechanisms associated with intracellular signaling pathway, anti-oxidative stress and anti-inflammation. In addition, the relationship of hyperglycemia and hyperuricemia, and the possibly regulative role of anthocyanins against them, along with the effects of anthocyanins in clinical trial are mentioned.

Comparative analysis of the efficacy of angiotensin II receptor blockers for uric acid level change in asymptomatic hyperuricaemia

WHAT IS KNOWN AND OBJECTIVE

There is much controversy over how angiotensin II receptor blockers (ARB) or angiotensin-converting enzyme inhibitors (ACEI) affect blood uric acid levels. Though ARB is not used to lorcwer the uric acid concentration in the blood, losartan, one of the ARB series, is known to reduce the uric acid concentration in the blood and is a preferred drug for hypertensive patients with gout. However, there is no clear conclusive consideration which ARB should be selected for the patients who have simply increased uric acid concentration, other than gout patients. This research aims to compare the variations of the uric acid concentration in the blood in accordance with the prescription of ACEI or ARB targeting patients who were not diagnosed with gout.

METHODS

This research was conducted on the patients who were, for the first time, prescribed ACEI or ARB for a total of 7 years from January 2009 to December 2015. This study has extracted the uric acid values after between 60 days and 120 days (average 90 days, defined as Visit 1) on the basis of the first prescription date of ACEI or ARB.

RESULTS AND DISCUSSION

In this study, ACEI was 17.0% of usage (3787/22 293 patients) and ARB was 83.0% (18 506/22 293 patients). Unlike ACEI (5.91 ± 0.03 vs 5.86 ± 0.03 mg/dL, P = .059), ARB showed a statistically significant decrease after 3 months (5.71 ± 0.01 vs 5.69 ± 0.01 mg/dL, P = .023). In the case of irbesartan (n = 1530, 6.13 ± 0.06 mg/dL vs 5.89 ± 0.05 mg/dL, P < .001) and olmesartan (n = 2719, 5.70 ± 0.04 mg/dL vs 5.63 ± 0.03 mg/dL, P = .008), the decrease in the uric acid after 3 months was revealed as statistically significant. In elderly aged over 60 years, only irbesartan (n = 855, 5.75 ± 0.07 mg/dL vs 5.59 ± 0.07 mg/dL, P = .006) showed a significant decrease in the uric. When the eGFR was less than 60 mL/min/1.73 m² , both ACEI (n = 1108, 6.95 ± 0.07 mg/dL vs 6.73 ± 0.07 mg/dL, P = .001) and ARB (n = 5280, 6.88 ± 0.03 vs 6.60 mg/dL ± 0.03 mg/dL, P < .001) showed a significant decrease in the uric acid.

WHAT IS NEW AND CONCLUSION

Although all types of ACEIs and ARBs are being prescribed with similar purposes, ARB (or ACEI) medication does not have a class effect and has varying effects on uric acid levels. The decreases in uric acid levels were relatively small. ARBs seem to be more advantageous than ACEIs for hyperuricaemia patients without gout who are aiming to maintain uric acid decrease levels. Furthermore, irbesartan can be a good substitute for losartan in view of the fact that at least the uric acid level is not increased.

Evaluation of electrochemical quartz crystal microbalance based sensor modified by uric acid-imprinted polypyrrole

Uric acid-imprinted polypyrrole-based (MIP_(UA)-Ppy) electrochemical quartz crystal microbalance sensor (EQCM) was developed. Experiments and theoretical calculations were focused on molecular interactions between uric acid molecule and: i) polypyrrole imprinted by uric acid (MIP_(UA)-Ppy) ii) polypyrrole film without any molecular imprints (NIP-Ppy). Resonant frequency differences during electrochemical deposition of MIP_(UA)-Ppy and NIP-Ppy films were observed and were attributed to the phenomenon of molecule capture within formed Ppy matrix. EQCM-resonators modified by MIP-Ppy showed the following advantages: selectivity, qualitative response, cost-effectiveness, and simple procedure. The selectivity of MIP_(UA)-Ppy was tested by the replacement of uric acid in the PBS solution with several different concentrations of caffeine and glucose. Langmuir isotherm based molecular adsorption model was applied to evaluate the interaction of MIP_(UA)-Ppy with uric acid. From experimental results calculated the standard Gibbs free energy of association (ΔG_a) of uric acid with MIP_(UA)-Ppy is -16.4 ± 2.05 kJ/mol and with NIP-Ppy is -13.3 ± 8.56 kJ/mol ΔG values illustrate that the formation of uric acid complex with MIP_(UA)-Ppy is thermodynamically more favourable than that for complexation with NIP-Ppy.

A Europium-based MOF Fluorescent Probe for Efficiently Detecting Malachite Green and Uric Acid

Lanthanide (such as Tb and Eu) metal-organic frameworks (MOFs) have been widely used in fluorescent probes because of their multiple coordination modes and brilliant fluorescence characteristic. Many lanthanide MOFs were applied in detecting metal ions, inorganic anions, and small molecules. However, it's rarely reported that Ln-MOF was devoted to detecting malachite green (MG) and uric acid (UA). We prepared a europium-based metal-organic framework (Eu-TDA) (TDA = 2,5-thiophenedicarboxylic acid group). Luminescence studies demonstrated that Eu-TDA can rapidly detect MG and UA with excellent selectivity and sensitivity, where individual quenching efficiency K_sv (MG: 5.8 × 10⁵ M^-1; UA: 4.15 × 10⁴ M^-1) and detection limit (MG: 0.0221 μM; UA: 0.689 μM) were regarded as the excellent MOF sensors for detecting MG and UA. The quenching of Eu-TDA's fluorescence emission by MG and UA was likely due to the spectral overlap, energy transfer, and competition. Among 11 metal cations and 14 anions, Eu-TDA can quickly and effectively recognize MG and UA with highly selective and sensitive properties. Our method possesses potential application in detecting UA in human blood and MG in the fishpond.

Prognostic value of serum uric acid levels in patients with non-STEMI undergoing percutaneous coronary intervention

BACKGROUND

Because myocardial infarction in young adults is rare, there has been limited research on the condition in this patient group. Very few data are available regarding the long-term outcomes of patients under 40 years of age with non-ST-segment elevation myocardial infarction (NSTEMI) undergoing invasive treatments. The prognostic value of uric acid (UA) in young patients with NSTEMI who undergo percutaneous coronary intervention (PCI) has also not been studied. The purpose of this study was to evaluate the long-term clinical outcomes of this specific subset of young patients. In addition, we aimed to identify the role of serum UA in predicting the long-term prognosis of young patients with NSTEMI who have undergone PCI.

METHODS

We performed a retrospective analysis of 213 young adult patients (≤40 years old) with NSTEMI who underwent PCI during their hospitalization at our tertiary referral center.

RESULTS

The mean age of the 213 patients was 36.8 ± 3.3 years (range, 21-40 years). The median follow-up was 930 days. Our patients were predominantly male (88.3%) and the most frequent traditional cardiovascular risk factors were smoking and dyslipidemia. Baseline TIMI flow 0-1, estimated glomerular filtration rate (eGFR), and UA were found to be independently correlated with long-term major adverse cardiovascular events (MACEs) in multivariate Cox regression analysis.

CONCLUSION

In the present study, baseline TIMI flow 0-1, admission eGFR, and UA levels were correlated with MACEs during long-term follow-up in young patients with NSTEMI.

Uric acid variability at midlife as an independent predictor of coronary heart disease and all-cause mortality

Background

Serum uric acid (SUA) has long been associated with cardiovascular disease. Variability of serum uric acid (SUA) has seldom been examined in association with long-term morbidity and mortality. Therefore, we aimed to investigate the association between SUA variability and long-term all-cause and specific-cause mortality.

Methods

Among 10,059 men, aged 40–65, tenured civil servants and municipal employees in Israel, 8822 participants who were examined in 1963, 1965 and 1968 had assessment of diabetic and coronary morbidity status and SUA levels. We conducted analysis examining whether the standard deviations (SD) of Z-scores of SUA across study visits predicted coronary heart disease (CHD) and mortality. Hazard ratios (HR) associated with the SD of SUA-Z were calculated for stroke, CHD mortality and all-cause mortality associated with quartiles of the above variability.

Results

Multivariate analysis of 18-year CHD mortality yielded a significant association with the 1963–1968 SD of SUA-Z with age adjusted HR of CHD mortality of 0.97 (95% CI, 0.8–1.19), 1.05 (95% CI, 0.87–1.28) and 1.37 (95% CI, 1.15–1.65) for quartiles 2 to 4 respectively). The results of all-cause mortality similarly and strongly indicated increasing age-adjusted mortality risk with increasing SD of SUA-Z: HR = 1.08 (95% CI, 0.97–1.21), 1.15 (1.03–1.28) and 1.37 (1.23–1.51). No association was observed between the SD of SUA-Z and stroke mortality.

Conclusion

In this cohort of tenured male workers, with diverse occupations, higher variability of SUA measurement taken over 5 years was clearly predictive of 18-year CHD and all-cause mortality, above and beyond the SUA levels proper.

Determination of Uric Acid in Co-Presence of Dopamine and Ascorbic Acid Using Cuprous Oxide Nanoparticle-Functionalized Graphene Decorated Glassy Carbon Electrode

Cuprous oxide nanoparticles (Cu2O NPs) were dispersed into a graphene oxide (GO) solution to form a homogeneous Cu2O-GO dispersion. After this, the cuprous oxide nanoparticles were functionalized to electrochemically reduce the graphene oxide decorated glassy carbon electrode (Cu2O-ErGO/GCE). This was prepared by coating the Cu2O-GO dispersion onto the surface of the glassy carbon electrode (GCE), which was followed by a potentiostatic reduction process. An irreversible two-electron reaction of uric acid (UA) was observed at the voltammetric sensor. Moreover, the high concentrations of dopamine (DA) and ascorbic acid (AA) hardly affected the peak current of UA, which suggested that Cu2O-ErGO/GCE have excellent selectivity for UA. This is probably because the response peaks of the three compounds are well-separated from each other. The oxidation peak current was proportional to the concentration of UA in the ranges of 2.0 nM−0.6 μM and 0.6 μM−10 μM, respectively, with a low limit of detection (S/N = 3, 1.0 nM) after an accumulation time of 120 s. Cu2O-ErGO/GCE was utilized for the rapid detection of UA in human blood serum and urine samples with satisfactory results.

Synthesis of Heart/Dumbbell-Like CuO Functional Nanostructures for the Development of Uric Acid Biosensor

It is always demanded to prepare a nanostructured material with prominent functional properties for the development of a new generation of devices. This study is focused on the synthesis of heart/dumbbell-like CuO nanostructures using a low-temperature aqueous chemical growth method with vitamin B₁₂ as a soft template and growth directing agent. CuO nanostructures are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. CuO nanostructures are heart/dumbbell like in shape, exhibit high crystalline quality as demonstrated by XRD, and have no impurity as confirmed by XPS. Apparently, CuO material seems to be porous in structure, which can easily carry large amount of enzyme molecules, thus enhanced performance is shown for the determination of uric acid. The working linear range of the biosensor is 0.001 mM to 10 mM with a detection limit of 0.0005 mM and a sensitivity of 61.88 mV/decade. The presented uric acid biosensor is highly stable, repeatable, and reproducible. The analytical practicality of the proposed uric acid biosensor is also monitored. The fabrication methodology is inexpensive, simple, and scalable, which ensures the capitalization of the developed uric acid biosensor for commercialization. Also, CuO material can be used for various applications such as solar cells, lithium ion batteries, and supercapacitors.

Integrative analysis of transcriptomic and metabolomic data via sparse canonical correlation analysis with incorporation of biological information

Integrative analysis of high dimensional omics data is becoming increasingly popular. At the same time, incorporating known functional relationships among variables in analysis of omics data has been shown to help elucidate underlying mechanisms for complex diseases. In this article, our goal is to assess association between transcriptomic and metabolomic data from a Predictive Health Institute (PHI) study that includes healthy adults at a high risk of developing cardiovascular diseases. Adopting a strategy that is both data-driven and knowledge-based, we develop statistical methods for sparse canonical correlation analysis (CCA) with incorporation of known biological information. Our proposed methods use prior network structural information among genes and among metabolites to guide selection of relevant genes and metabolites in sparse CCA, providing insight on the molecular underpinning of cardiovascular disease. Our simulations demonstrate that the structured sparse CCA methods outperform several existing sparse CCA methods in selecting relevant genes and metabolites when structural information is informative and are robust to mis-specified structural information. Our analysis of the PHI study reveals that a number of gene and metabolic pathways including some known to be associated with cardiovascular diseases are enriched in the set of genes and metabolites selected by our proposed approach.

An evaluation of longitudinal changes in serum uric acid levels and associated risk of cardio-metabolic events and renal function decline in gout

OBJECTIVE

Gout patients have a high burden of co-morbid conditions including diabetes mellitus (DM), chronic kidney disease (CKD), and cardiovascular disease (CVD). We sought to evaluate the association between changes in serum uric acid (SUA) levels over time and the risk of incident DM, CVD, and renal function decline in gout patients.

METHODS

An observational cohort study was conducted among enrollees of private health insurance programs in the US between 2004 and 2015. Gout patients were included on the index date of a SUA measurement ≥6.8 mg/dl. The exposure of interest was cumulative change in SUA levels from baseline. Hazard ratios (HR) and 95% confidence intervals (CI) for incident DM, incident CVD, and renal function decline (≥30% reduction in glomerular filtration rate) were derived using marginal structural models with stabilized inverse probability weights accounting for baseline confounders (age, gender, co-morbidities, co-medications) and time-varying confounders (serum creatinine, blood urea nitrogen, glycated hemoglobin).

RESULTS

Among 26,341 patients with gout, the average age was 62, 75% were men, and the median baseline SUA was 8.6 mg/dl (interquartile range 7.7 to 9.5). The incidence rates/100 person-years (95% CI) were 1.63 (1.51-1.75) for DM, 0.77 (0.70-0.84) for CVD, and 4.32 (4.14-4.49) for renal function decline. The adjusted HR (95% CI) per 3 mg/dl reduction in SUA, corresponding on average to achieving the target level of <6 mg/dl in this population, was 1.04 (0.92-1.17) for DM, 1.07 (0.89-1.29) for CVD, and 0.85 (0.78-0.92) for renal function decline.

CONCLUSIONS

Reduction in SUA in patients with gout may be associated with a reduced risk of renal function decline, but not with DM or CVD.

Hyperuricemia as a prognostic factor after acute coronary syndrome

BACKGROUND AND AIMS

Many studies have reported the independent association between uric acid and cardiovascular disease, its role as a risk predictor for outcomes in people with acute coronary syndrome remains controversial. This study aims to assess the association between hyperuricemia and medium/long-term clinical outcomes in people with acute coronary syndrome and determine whether adding hyperuricemia to the GRACE score improves its predictive capability.

METHODS

This cohort study included patients admitted for acute coronary syndrome between 2008 and 2013. Outcomes were cardiovascular and total mortality, and major cardiovascular events. We used a multivariate model to adjust for potential confounding covariates and presented event rates with Kaplan-Meier curves. After adding hyperuricemia to the GRACE score, we compared scores from the reclassification table and the net reclassification improvement.

RESULTS

1119 participants were included and followed-up for a mean of 36 months. Multivariate models showed hyperuricemia was independently associated with higher cardiovascular mortality (HR:1.91; 95% CI:1.32-2.76; p < 0.01), higher all-cause mortality (HR:1.59; 95% CI:1.18-2.15; p < 0.01) and higher major cardiovascular event rates (HR:1.36; 95% CI:1.11-1.67; p < 0.01). The hyperuricemia addition to GRACE score led to reclassifying 26% of the participants, and net reclassification improvement was 34%. However, the area under the curve increase was 0.009 and not statistically significant (p > 0.05).

CONCLUSIONS

Hyperuricemia is associated with higher medium/long-term mortality and major cardiovascular event rates in patients following acute coronary syndrome. The addition of hyperuricemia to the GRACE score seems to improve risk classification but the discrimination of the new predictive model did not change. Hyperuricemic patients had higher all-cause mortality in medium and high-risk score categories.

A bimetallic nanoparticle/graphene oxide/thionine composite-modified glassy carbon electrode used as a facile ratiometric electrochemical sensor for sensitive uric acid determination

A novel and facile ratiometric electrochemical sensor was developed for sensitive determination of uric acid.

A multiplex paper-based nanobiocatalytic system for simultaneous determination of glucose and uric acid in whole blood

In this work, a versatile point-of-care assay platform based on a microfluidic paper-based analytic device (μPAD) was developed for the simultaneous detection of multiple targets.

Mimicking oxygen delivery and waste removal functions of blood

In addition to immunological and wound healing cell and platelet delivery, ion stasis and nutrient supply, blood delivers oxygen to cells and tissues and removes metabolic wastes. For decades researchers have been trying to develop approaches that mimic these two immediately vital functions of blood. Oxygen is crucial for the long-term survival of tissues and cells in vertebrates. Hypoxia (oxygen deficiency) and even at times anoxia (absence of oxygen) can occur during organ preservation, organ and cell transplantation, wound healing, in tumors and engineering of tissues. Different approaches have been developed to deliver oxygen to tissues and cells, including hyperbaric oxygen therapy (HBOT), normobaric hyperoxia therapy (NBOT), using biochemical reactions and electrolysis, employing liquids with high oxygen solubility, administering hemoglobin, myoglobin and red blood cells (RBCs), introducing oxygen-generating agents, using oxygen-carrying microparticles, persufflation, and peritoneal oxygenation. Metabolic waste accumulation is another issue in biological systems when blood flow is insufficient. Metabolic wastes change the microenvironment of cells and tissues, influence the metabolic activities of cells, and ultimately cause cell death. This review examines advances in blood mimicking systems in the field of biomedical engineering in terms of oxygen delivery and metabolic waste removal.

Serum uric acid as a potential marker for heart failure risk in men on antihypertensive treatment: The British Regional Heart Study

The role of serum uric acid (SUA) as a prognostic marker for incident heart failure (HF) in hypertensive subjects is uncertain. We have prospectively examined the relationship between SUA and incident HF in 3440 men aged 60–79 years separately in those on and not on antihypertensive treatment who were followed up for a mean period of 15 years. Men on SUA lowering drugs and those with history of HF or myocardial infarction were excluded. There were 260 incident HF cases. The men were divided into three groups of SUA concentrations/levels (< 350, 350–410 and > 410 μmol/L). Raised SUA was associated with significantly increased risk of HF in men on antihypertensive treatment (N = 949) but not in those without (N = 2491) (p = 0.003 for interaction). In men on antihypertensive treatment those with hyperuricemia (> 410 μmol/L) had the most adverse biological risk profile for HF including the highest rates of atrial fibrillation and renal dysfunction and the highest mean level of BMI, c-reactive protein and cardiac function (cardiac troponin T). Treated hypertensive men with SUA levels > 410 μmol/L showed an increase in risk of HF of more than twofold compared to those on treatment with levels < 350 μmol/L even after adjustment for lifestyle characteristics and biological risk factors [adjusted hazard ratio 2.26 (1.23,4.15)]. SUA improved prediction of HF beyond routine conventional risk factors (p = 0.02 for improvement in c-statistics). SUA as a marker of increased xanthine oxidase activity may be a useful prognostic marker for HF risk in older men on antihypertensive treatment.

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Raised serum uric acid (SUA) is associated with increased risk of heart failure in older men on antihypertensive treatment

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Treated hypertensive men with raised SUA have the most adverse risk profile for heart failure including underlying ischaemia

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Monitoring of SUA in older hypertensive patients may identify high risk patients who would benefit from further investigation

Nanomolar Level Detection of Uric Acid in Blood Serum and Pest-Infested Grain Samples by an Amphiphilic Probe

A pyrene based amphiphilic receptor has been utilized in the nanomolar detection of uric acid at physiological pH in water. The compound shows a unique concentration-dependent modulation in optical response toward uric acid. In intramolecular/static excimer form (low concentration range), it displays a ratiometric response, while a "turn-off" sensing is observed specifically in the presence of intermolecular/dynamic excimer (high concentration range). The present protocol is then employed for the estimation of uric acid in blood serum samples of healthy individuals. Bland-Altman analysis in comparison to clinically approved uricase assay indicated the high accuracy of the present method. Additionally, the extent of insect infestation in stored grain samples was determined by measuring the uric acid content of their aqueous extracts. Low-cost color strips were developed for on-site detection of uric acid without involving any sophisticated instrument or trained personnel.

Study of ZnS Nanostructures Based Electrochemical and Photoelectrochemical Biosensors for Uric Acid Detection

Uric acid (UA) is a kind of purine metabolism product and important in clinical diagnosis. In this work, we present a study of ZnS nanostructures-based electrochemical and photoelectrochemical biosensors for UA detection. Through a simple hydrothermal method and varying the ratio of reaction solvents, we obtained ZnS nanomaterials of one-dimensional to three-dimensional morphologies and they were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). To fabricate the UA biosensor and study the effect of material morphology on its performance, ZnS nanomaterials were deposited on indium tin oxide (ITO) conducting glass and then coated with uricase by physical absorption. Three kinds of working electrodes were characterized by cyclic voltammetry method. The effect of material morphology on performance of UA detection was investigated via amperometric response based electrochemical method based on enzymatic reaction. The ZnS urchin-like nanostructures electrode shows better sensitivity compared with those made of nanoparticles and nanoflakes because of its high surface-area-to-volume ratio. The photoelectrochemical method for detection of UA was also studied. The sensitivity was increased 5 times after irradiation of 300 nm UV light. These results indicate that ZnS nanostructures are good candidate materials for developing enzyme-based UA biosensors.

Serum uric acid on admission predicts in-hospital mortality in patients with acute coronary syndrome

BACKGROUND

Despite the association between uric acid and cardiovascular disease has been known for decades, the prognostic value of serum uric acid (UA) in all clinical manifestations of acute coronary syndrome (ACS), namely ST-elevation myocardial infarction (STEMI), NSTEMI and unstable angina, has not been definitively assessed.

METHODS

This retrospective analysis included patients from previous SPAI and FAMI studies with the aim to investigate the association between serum uric acid and major adverse cardiovascular events at 180days from hospital admission.

RESULTS

1548 patients were considered and divided in four groups, according UA concentration. Uricemia was significantly associated with gender, BMI, arterial hypertension, HDL-cholesterol, triglycerides, metabolic syndrome and glomerular filtration rate in univariate analysis. Multivariate logistic regression indicated that UA >6.0mg/dL on admission increased the risk of in-hospital mortality in overall population (OR 2.9, 95%CI 1.4-6.1; p=0.0057) and in patients with de novo ACS (OR 3.2, 95%CI 1.5-6.8; p=0.0033). Comparable results were also obtained after adjusting the model for age, gender, body mass index, glomerular filtration rate, metabolic syndrome, acute revascularization and ethnicity. A positive correlation was observed between UA and C reactive protein concentrations in in-hospital deaths only (rho 0.41, p=0.027).

CONCLUSION

In patients with acute coronary syndrome, uricemia levels above the current international reference limit (6.0mg/dl) were associated with in-hospital mortality, independently from ethnicity and renal function.