Uric acid: role in cardiovascular disease and effects of losartan

Concentration of uric acid removed during dialysis. Estimated by multi wavelength and processed ultra violet absorbance spectra

The aim of this study was to estimate the concentration of uric acid (UA) optically by using original and processed ultra violet (UV) absorbance spectra's of the spent dialysate. Also the effect of using several wavelengths for estimation was examined.

Independent relationship of serum uric acid levels with leukocytes and coronary atherosclerotic burden

BACKGROUND AND AIM

Epidemiological studies have shown that increased serum uric acid (SUA) level is associated with coronary artery disease (CAD). Leukocytes have been shown to play an important role in the atherosclerotic process. The aim of the study was to investigate whether there is any relationship among SUA, leukocyte counts and coronary atherosclerotic burden in patients who are suspected of having CAD.

METHOD AND RESULTS

We enrolled 690 eligible patients who had undergone coronary angiography between October 2005 and June 2006 in a consecutive manner. The relationship of SUA with total and differential leukocyte counts and CAD was investigated. Serum uric acid levels (5.57+/-1.64 vs 4.63+/-1.27 mg/dl, p<0.001) and leukocytes were higher in patients with CAD than those with normal coronary arteries (NCA). When we divided the patients into four groups according to the quartiles of SUA, we found that the monocyte count was prominently related with SUA (478+/-165, 553+/-177, 565+/-199 and 607+/-229 mm(-)(3), Q1-Q4, p<0.001). In multivariate analysis, SUA was an independent predictor of CAD (OR, 1.270; 95% CI, 1.087-1.484, p=0.003). When we performed multiple linear regression analyses to determine the independent predictors of inflammatory cells in blood, we found a strong, positive and independent relationship between SUA with neutrophils (beta+/-SE: 206+/-60, p=0.001) and monocytes (beta+/-SE: 35+/-7, p<0.001).

CONCLUSION

Our study results demonstrated that neutrophils and monocytes which play an important role in inflammation and atherosclerosis were independently related with SUA. This finding suggests an important epidemiologic relation and may provide a possible causative mechanism of SUA in atherosclerotic process.

Role of ankle-brachial pressure index as a predictor of coronary artery disease severity in patients with diabetes mellitus

BACKGROUND

Previous studies have reported a close correlation between low ankle-brachial pressure index (ABPI) and various cardiovascular risk factors. However, despite the well-established potential hazards of consequent coronary artery disease (CAD), no data exist on the relationship between ABPI and the severity of CAD, particularly in patients with diabetes mellitus (DM).

METHODS

A total of 840 patients ranging from 35 to 87 years of age (mean [+/- SD] 63.9+/-10.2 years) with suspected CAD in a clinical practice were enrolled. All patients underwent ABPI measurements and coronary angiography. Patients were divided into four groups according to the results of ABPI measurements and the presence or absence of DM: group A had an ABPI value of at least 0.9 but no DM (A-/D-); group B had an ABPI value of at least 0.9 and DM (A-/D+); group C had an ABPI of less than 0.9 but no DM (A+/D-); and group D had an ABPI value of less than 0.9 and DM (A+/D+).

RESULTS

Age was significantly higher in the A+ (groups C and D) than the A- patients (groups A and B). Moreover, men predominated in all four groups. Comparisons of sex distribution among the four groups revealed that group D had the highest percentage of women, while group A had the lowest. Total cholesterol level did not differ among the four groups, although group D tended to have the highest result. Patients in group D had the highest percentages of hypertension, hypercholesterol, hypertriglyceride, low high-density lipoprotein cholesterol and high low-density lipoprotein cholesterol among the four groups. Group D exhibited the highest triglyceride and uric acid levels, the lowest high-density lipoprotein cholesterol level, and the highest metabolic syndrome criteria number and percentage of metabolic syndrome. Furthermore, group D had the highest mean lesion numbers, mean numbers of target vessel involvement, stenoses with type C classification and complex morphology lesions (chronic total occlusion, diffuse or calcified lesions) among the four groups. There were still significant differences in lesion numbers (P<0.001) and numbers of target vessel involvement (P<0.001) for ABPI predicting CAD severity after controlling for the effects of DM and age. The sensitivity, specificity, positive predictive value and negative predictive value of using an ABPI of less than 0.9 to predict CAD differed significantly between patients with and without DM.

CONCLUSIONS

ABPI is a useful noninvasive tool for predicting CAD severity, even in patients with DM.

Using new tools to define the genetic underpinnings of risky traits associated with coronary artery disease: the SardiNIA study

Genomewide association studies are increasingly being applied to search for novel genes that might underlie cardiovascular diseases. In this article, we briefly review the principles that underlie modern genetic analyses and provide several illustrations from the SardiNIA study of genomewide association studies for cardiovascular risk factor traits.

Vascular and metabolic effects of angiotensin II receptor blockers

Angiotensin II receptor blockers (ARBs) are widely used in patients with hypertension, heart failure and type 2 diabetes mellitus (T2DM). Several large clinical trials have demonstrated that these agents are effective in reducing cardiovascular mortality and morbidity. These benefits are partly independent of the degree of blood pressure reduction and most likely related to ARBs' anti-inflammatory, metabolic and vascular effects. Clinical studies showed that the anti-inflammatory effect of ARBs could be related to the dosage and/or the length of the treatment. In large clinical trials, ARBs have inconsistently reduced the risk of new-onset T2DM. Among ARBs, only losartan significantly reduced serum uric acid levels. Moreover, it has been demonstrated that ARBs improve endothelial dysfunction in patients with hypertension and/or coronary artery disease (CAD), while all but one of the studies proved that these agents could usually, after 6-12 months of therapy, induce regression of vascular hypertrophy in hypertensive patients. These positive effects could be relevant to vascular protection and, together with the blood pressure reduction, constitute the background of the improved outcome observed in clinical studies on mortality and/or morbidity in hypertensive, high-risk and CAD patients. The clinical significance of the different potency of ARBs needs to be investigated further in specific and adequately powered trials.

Cardiorespiratory capacity is associated with favourable cardiovascular risk profile in patients with Type 2 diabetes

OBJECTIVE

The aim of this study was to examine the interaction between cardiorespiratory capacity and cardiovascular risk factors in patients with Type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN/METHODS

A total of 92 patients with T2DM (40 men, 52 women) performed a symptom-limited exercise test on ergocycle, with continuous gas exchange measurement. All patients were overweight or obese (body mass index >25 kg/m(2)), with poor glycemic control (hemoglobin A(1c) >7%), but free from overt diabetic vascular complications. Anthropometric parameters, blood pressure (BP), cardiorespiratory fitness, glycemic and lipid profile, fibrinogen, plasminogen activator inhibitor-1, high-sensitivity C-reactive protein (hsCRP), insulin resistance, and 24-h urinary albumin excretion (UAE) were measured. Based on the median Vo(2) peak value, participants were placed into low fitness (LF, n=46) or moderate fitness group (MF, n=46).

RESULTS

In univariate analysis, exercise capacity correlated with systolic (r=-0.349) and diastolic BP (r=-0.441), waist circumference (r=-0.345), total cholesterol (r=-0.348), high-density lipoprotein (HDL) (r=0.362), UAE (r=-0.486), homeostasis model assessment (HOMA-IR) (r=-0.467), uric acid (r=-0.316), and hsCRP (r=-0.217, only in women subgroup) (P<.05). With the exception of the latter three variables, the above associations remained significant after controlling for age and sex in multiple regression analysis (P<.05). Compared to LF group, patients in MF group showed significantly higher levels of HDL and lower levels of BP, waist circumference, hsCRP, and HOMA-IR (P<.05). In addition to this, UAE tended to be lower in fit patients (P=.054).

CONCLUSIONS

Low cardiorespiratory fitness seems to be independently associated with most traditional and emerging cardiovascular risk factors in patients with T2DM. Even a moderate increase of cardiorespiratory fitness exerts beneficial effects on cardiovascular risk profile.

A multicentre study of an enhanced optical method for measuring concentration of uric acid removed during dialysis

The aim of this study was to compare concentration measurements of uric acid (UA) removed during dialysis by two algorithms based on UV-absorbance and the 1st derivate of UV absorbance. Ten uremic patients from Tallinn and ten from Linköping, during 30+40 haemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linköping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a double-beam spectrophotometer. UV absorbance and derivate of UV absorbance was transformed into UA concentration in the spent dialysate using the regression models from the calibration set of material, noted as UV-absorbance (UV_A) and the 1st derivate of UV absorbance (UV_D) method. These models were tested on validation set of material and concentrations of UA from the two methods were compared regarding mean values and SD. Mean concentration of UA were 52.7 +/- 25.0 micromol/l measured at the chemical laboratory (UA_Lab), 54.9 +/- 23.8 micromol/l determined by UV_A and 52.9 +/- 23.0 micromol/l determined by UV_D. The results of mean concentrations were not significantly different (p > or = 0.54). The systematic errors were -7.8 % and -3.3% and random errors were 15.8 % and 10.4 % using UV_A and UV_D respectively. The systematic and random errors were significantly different (p < 0.05) indicating that the new algorithm enables more accurate UA estimation.

Gout Induced by Intoxication of Sodium Bicarbonate in Korean Native Broilers

Gout is a metabolic disorder that results in hyperuricemia and the deposition of positively birefringent monosodium urate crystals in various parts of the body. Intoxication of sodium bicarbonate (SBC) for 35 days in Korean native broilers was investigated. Sixty birds, aged 2 weeks, divided into 5 groups were exposed to excess SBC: 2 g/L (group A), 7.5 g/L (group B), 20 g/L (group C), 40 g/L (group D). Toxicopathological examination of all exposed birds revealed the manifestation of visceral and articular gout in group C, while birds of group D showed acute kidney damage with manifestation of excessive visceral gout. Interestingly, few birds in group D also showed signs of rare condition of acute articular gout. Dose-dependent increments in erythrocytic count, hematocrit values, and hemoglobin levels of the exposed birds were observed. Hypernatremia, hyperuricemia, hypokalemia, and hypochloremia were common findings among exposed birds. Microscopic examination of birds that manifested visceral gout revealed significant urate deposit, tubular necrosis, and tophi formation in renal interstitium. These findings provide a pathophysiological link that SBC intoxication may support hyperuricemia, which is an independent risk factor for gout and other renal dysfunctions. Further study is required to delineate the effect of lowering uric acid on progression of gout and other renal diseases.

Molecule-specific effects of angiotensin II-receptor blockers independent of the renin-angiotensin system

Because all clinically approved angiotensin-receptor blockers (ARBs) have good safety profiles and share the ability to block angiotensin II type 1 (AT1) receptors and reduce blood pressure, it is tempting to assume that all ARBs will yield equivalent degrees of cardiovascular protection. However, such a belief depends on the tacit assumption that with appropriate dosing, all ARBs will also share the same ability to counteract other pathogenetic determinants of cardiovascular disease beyond those involving the renin-angiotensin system. Accumulating evidence from multiple laboratories has shown that this assumption is incorrect and indicates that some ARBs are characterized by an unusual ability to affect potential mechanisms of cardiovascular disease involving more than just the renin-angiotensin system. Ultimately, large-scale clinical trials will be required to better understand the clinical importance of the mechanistic effects of ARBs that involve more than just inhibition of the renin-angiotensin system. Meanwhile, given the many functional differences among ARBs that are not mediated by AT1 receptor blockade, the effects of any particular ARB on cardiovascular outcomes should not be assumed to apply equally to all ARBs let alone to other drugs that inhibit the renin-angiotensin system through different mechanisms.

Small arterial elasticity predicts the extent of coronary artery disease: Relationship with serum uric acid

BACKGROUND

Arterial elasticity has been previously linked to atherosclerotic vascular disease states. Serum uric acid level has been recently associated with increased arterial stiffness, but to what extent serum uric acid reflects angiographic coronary artery status and vessel compliance remains to be established. In this study we aimed to evaluate the association of arterial elasticity indexes, serum uric acid and the presence and extent of angiographic coronary artery disease (CAD) in patients with chronic stable angina.

METHODS

One hundred and eight consecutive patients attending for elective coronary angiography were investigated. The severity of CAD was expressed using the Gensini score. Quantitative analysis of the arterial elasticity was performed by applanation tonometry. Serum uric acid was measured in all participants. Stepwise multiple linear regression analysis was used to identify the independent correlates of the Gensini score.

RESULTS

After adjustment for age, gender, common cardiac risk factors and cardiovascular drugs, small artery elasticity index (SAEI) (p<0.001) and serum uric acid (p<0.001) were independently correlated with the severity of CAD. Stepwise multiple linear regression analysis was also used to identify independent correlates of the SAEI. Serum uric acid emerged as the only independent correlate of SAEI (p<0.001).

CONCLUSIONS

SAEI independently reflects the extent of CAD in patients with chronic stable angina. This relationship is chiefly mediated by serum uric acid. Our data add to the growing evidence that serum uric acid may be a marker of arterial stiffness and atherosclerotic burden.

Association between serum uric acid and prehypertension among US adults

BACKGROUND

Experimental evidence supports a causal role of serum uric acid in hypertension development. Previous epidemiologic studies demonstrated an association between uric acid and hypertension; however, data from non-Caucasian ethnicities are limited. Currently there are few data available on the association between serum uric acid level and clinically relevant blood pressure (BP) categories earlier in the disease continuum, when hypertension prevention efforts may be applicable. We examined the association between serum uric acid and prehypertension in a nationally representative sample of US adults.

METHODS

Cross-sectional study among 4,817 National Health and Nutrition Examination Survey 1999-2002 participants aged >or=18 years without hypertension. The main outcome of interest was the presence of prehypertension (systolic BP 120-139 mmHg or diastolic BP 80-89 mmHg) (n = 1913).

RESULTS

Higher serum uric acid levels were positively associated with prehypertension, independent of smoking, body mass index (BMI), diabetes, kidney function and other confounders. The multivariable odds ratio (OR) [95% confidence intervals (CI)] comparing quartile 4 of uric acid (>356.9 micromol/l) to quartile 1 (<237.9 micromol/l) was 1.96 (1.38-2.79), P trend = 0.0016. This association persisted in separate analysis among men and women. The results were consistent in subgroup analyses by categories of race-ethnicity, education, age, smoking and BMI. In nonparametric models, the positive association between serum uric acid and prehypertension appeared to be present across the full range of uric acid, without any threshold effect.

CONCLUSIONS

Higher serum uric acid levels are associated with prehypertension in a nationally representative sample of US adults, free of cardiovascular disease (CVD) and hypertension.

Serum uric acid shows a J-shaped trend with coronary mortality in non-insulin-dependent diabetic elderly people. The CArdiovascular STudy in the ELderly (CASTEL)

The relationship between serum uric acid (SUA) and risk of coronary heart disease (CHD) mortality remains controversial, particularly in diabetic subjects. The aim of the present study is to evaluate whether SUA independently predicts CHD mortality in non-insulin-dependent elderly people from the general population and to investigate the interactions between SUA and other risk factors. Five hundred and eighty-one subjects aged >/=65 years with non-insulin-dependent diabetes mellitus were prospectively studied in the frame of the CArdiovascular STudy in the ELderly (CASTEL). Historical and clinical data, blood tests and 12-year fatal events were recorded. SUA as a continuous item was divided into tertiles and, for each tertile, adjusted relative risk (RR) with 95% confidence intervals (CI) was derived from multivariate Cox analysis. CHD mortality was predicted by SUA in a J-shaped manner. Mortality rate was 7.9% (RR 1.28, CI 1.05-1.72), 6.0% (reference tertile) and 12.1% (RR 1.76, CI 1.18-2.27) in the increasing tertiles of SUA, respectively, without any difference between genders. In diabetic elderly subjects, SUA independently predicts the risk of CHD mortality in a J-shaped manner.

Independent impact of gout on mortality and risk for coronary heart disease

BACKGROUND

Although gout and hyperuricemia are related to several conditions that are associated with reduced survival, no prospective data are available on the independent impact of gout on mortality. Furthermore, although many studies have suggested that hyperuricemia is associated with cardiovascular disease (CVD), limited data are available on the impact of gout on CVD.

METHODS AND RESULTS

Over a 12-year period, we prospectively examined the relation between a history of gout and the risk of death and myocardial infarction in 51,297 male participants of the Health Professionals Follow-Up Study. During the 12 years of follow-up, we documented 5825 deaths from all causes, which included 2132 deaths from CVD and 1576 deaths from coronary heart disease (CHD). Compared with men without history of gout and CHD at baseline, the multivariate relative risks among men with history of gout were 1.28 (95% confidence interval [CI], 1.15 to 1.41) for total mortality, 1.38 (95% CI, 1.15 to 1.66) for CVD deaths, and 1.55 (95% CI, 1.24 to 1.93) for fatal CHD. The corresponding relative risks among men with preexisting CHD were 1.25 (95% CI, 1.09 to 1.45), 1.26 (95% CI, 1.07 to 1.50), and 1.24 (95% CI, 1.04 to 1.49), respectively. In addition, men with gout had a higher risk of nonfatal myocardial infarction than men without gout (multivariate relative risk, 1.59; 95% CI, 1.04 to 2.41).

CONCLUSIONS

These prospective data indicate that men with gout have a higher risk of death from all causes. Among men without preexisting CHD, the increased mortality risk is primarily a result of an elevated risk of CVD death, particularly from CHD.

The effect of mild hyperuricemia on urinary transforming growth factor beta and the progression of chronic kidney disease

Although mild hyperuricemia is common in patients with renal disease, it has usually been considered a marker of reduced nephron mass rather than a risk factor for progression of kidney disease. On the other hand, experiments in a rat model demonstrated important deleterious effects of mild hyperuricemia on several aspects of renal structure and function. In the present investigation, the impact of the discontinuation of allopurinol therapy on the control of hypertension and the rate of progression of chronic kidney disease was considered. The present work involved 50 patients, suffering from stage 3 and 4 chronic kidney disease. All of them were on chronic allopurinol therapy for the treatment of mild hyperuricemia. Their blood pressure, serum creatinine and uric acid levels were followed for 12 months following allopurinol withdrawal. Urinary transforming growth factor beta-1 (TGF-beta1) was assayed by a solid-phase enzyme-linked immunosorbent assay. After allopurinol withdrawal, significant worsening of hypertension, significant acceleration of the rate of loss of kidney function and a significant increase in the urinary excretion of TGF-beta1 were observed in the group of patients who were not receiving pharmacological blockers of the renin-angiotensin system. In conclusion, asymptomatic hyperuricemia has a deleterious effect on the progression of chronic kidney disease and the control of hypertension. This effect was blocked by treatment with renin-angiotensin system blockers.

Serum Levels of Uric Acid and Diabetes Mellitus Influence Survival after Surgery for Primary Hyperparathyroidism: A Prospective Cohort Study

BACKGROUND

Primary hyperparathyroidism (pHPT) is associated with an increased mortality attributable to cardiovascular disease (CVD), suggested to be alleviated by surgery. The exact mechanism of the beneficial influence of parathyroidectomy on survival is unknown. Furthermore, studies suggest that there is no increased mortality compared to the mortality rate in the general population during recent years. This study therefore investigated relative survival (RS), as well overall mortality associated with the clinical and biochemical variables in patients undergoing operation for sporadic pHPT. Furthermore, the influence of surgery on biochemical variables associated with pHPT was analyzed.

METHODS

A group of 323 patients with sporadic pHPT operated between September 1989 and July 2003 were followed from surgery over a 10-year period. The median and mean follow-up time was 69 and 70 months, respectively (range: 1-120 months). Relative survival (RS) was calculated, and the impact of clinical and biochemical variables on overall death were evaluated.

RESULTS

Postoperatively, serum levels of triglycerides and uric acid decreased. Glucose levels and glomerular filtration rate remained unchanged. A decreased RS was evident during the latter part of the 10 year follow-up period. In the multivariate Cox-analysis, diabetes mellitus (hazard ratio [HR] = 2.8, 95%; confidence interval [CI] 1.2-6.7), and the combination of an increased level of serum uric acid and cardiovascular disease (CVD) (HR = 8.6, 95%; CI 1.5-49.7) was associated with a higher mortality. The increased risk of death was evident for patients with persistently increased levels of uric acid postoperatively (HR = 4.8, 95%; CI = 1.4-16.01).

CONCLUSIONS

Patients undergoing operation for pHPT had a decreased RS during a 10-year follow-up compared to the general population. This decrease in RS is associated with diabetes mellitus and increased levels of uric acid pre-and postoperatively.

Xanthine oxidoreductase is a regulator of adipogenesis and PPARgamma activity

In an effort to identify novel candidate regulators of adipogenesis, gene profiling of differentiating 3T3-L1 preadipocytes was analyzed using a novel algorithm. We report here the characterization of xanthine oxidoreductase (XOR) as a novel regulator of adipogenesis. XOR lies downstream of C/EBPbeta and upstream of PPARgamma, in the cascade of factors that control adipogenesis, and it regulates PPARgamma activity. In vitro, knockdown of XOR inhibits adipogenesis and PPARgamma activity while constitutive overexpression increases activity of the PPARgamma receptor in both adipocytes and preadipocytes. In vivo, XOR -/- mice demonstrate 50% reduction in adipose mass versus wild-type littermates while obese ob/ob mice exhibit increased concentrations of XOR mRNA and urate in the adipose tissue. We propose that XOR is a novel regulator of adipogenesis and of PPARgamma activity and essential for the regulation of fat accretion. Our results identify XOR as a potential therapeutic target for metabolic abnormalities beyond hyperuricemia.

The role of renin–angiotensin system inhibition in the treatment of hypertension in metabolic syndrome: are all the angiotensin receptor blockers equal?

The metabolic syndrome (MetS) is a strong predictor of cardiovascular morbidity and mortality, as well as new Type 2 diabetes. MetS consists of visceral obesity, elevated blood pressure, impaired glucose metabolism, atherogenic dyslipidaemia (elevated triglycerides and low levels of high-density lipoprotein cholesterol), as well as other metabolic abnormalities. The underlying pathophysiology seems to be largely, but not uniquely, attributable to insulin resistance. Existing antihypertensive drugs were designed to lower blood pressure rather than to modify the metabolic abnormalities associated with hypertension. This review considers the role of renin-angiotensin system inhibition and especially the use of angiotensin receptor blockers (ARBs) in the treatment of hypertension in MetS. There are differences among ARBs. Among them is the uricosuric effect of losartan. Furthermore, telmisartan may function as a partial agonist of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma).

Review of the molecular pharmacology of Losartan and its possible relevance to stroke prevention in patients with hypertension

BACKGROUND

The Losartan Intervention For End-point reduction in hypertension (LIFE) study found that a losartan-based regimen, compared with an atenolol-based regimen, resulted in a significantly lower risk of stroke in hypertensive patients with left ventricular hypertrophy, despite similar reductions in blood pressure.

OBJECTIVE

The purpose of this review was to examine the molecular and pharmacologic mechanisms that may be associated with the different outcomes observed in the LIFE study.

METHODS

A PubMed/MEDLINE search of English-language articles (1990 to February 2006) with the terms angiotensin II antagonists or AIIAs or angiotensin receptor blockers or losartan or atenolol or beta blocker and terms including, but not limited to, atherosclerosis, left ventricular hypertrophy, carotid artery hypertrophy, fatty streaks, atrial fibrillation, arrhythmias, endothelial function, myocyte hypertrophy, myocardial fibrosis, platelet aggregation, tissue factor, plasminogen activator inhibitor-1, PAI-1, anti-inflammatory, uric acid, or oxidative stress.

RESULTS

Losartan's significant effect on stroke may be related to several possible mechanisms that are independent of blood-pressure reductions. These include improvements in endothelial function and vascular structure; decreases in vascular oxidative stress; reductions in left ventricular hypertrophy, reductions in myocardial fibrosis, or both; and modulation of atherosclerotic disease progression. Although some of these effects may be shared by other angiotensin II receptor antagonists (AIIAs), and perhaps other anti-hypertensive classes (eg, angiotensin-converting enzyme inhibitors), the ability of losartan to lower serum uric acid levels-a proposed independent risk factor for cardiovascular disease-appears to be a molecule-specific effect. Alternative explanations of the results of the LIFE study have also been hypothesized, including inappropriate choice of atenolol as an active comparator and differences in central pulse pressures between study groups.

CONCLUSIONS

This review of the literature suggests that losartan (and perhaps other AIIAs) may possess a number of properties, independent of its antihypertensive effects, that may be associated with decreased vulnerability of the plaque, myocardium, and blood.

The association between serum uric acid level and long-term incidence of hypertension: Population-based cohort study

Increasing experimental evidence, including recently developed animal models support a causal role for uric acid in the development of hypertension. However, it is not clear whether serum uric acid levels are independently associated with the long-term incidence of hypertension. We examined the association between serum uric acid levels and 10-year incidence of hypertension in a population-based cohort study based in Beaver Dam city and township, Wisconsin, US. We studied 2520 hypertension-free individuals (56.3% women, age: 43-84 years, 98% Caucasian) at the baseline examination (1988-1990). The main outcome of interest was hypertension (systolic blood pressure (BP) of 140 mm Hg or higher, diastolic BP 90 mm Hg or higher, or combination of self-reported high BP diagnosis and use of antihypertensive medications) incidence over 10 years among baseline normotensive individuals. Nine hundred and fifty-six individuals developed hypertension over a 10-year follow-up period. The relative risk (RR) (95% confidence intervals (CI)) of incident hypertension increased in a dose-dependent manner (P-trend < 0.05 in all models) with increasing uric acid quartiles. Multivariable RR (95% CI) comparing the highest quartile of serum uric acid (> or =390 micromol/l) to the lowest quartile (< or =260 micromol/l) was 1.65 (1.41-1.93). This association persisted in subgroup analyses by categories of smoking, alcohol intake, body mass index, baseline blood pressure and estimated glomerular filtration rate (GFR). In conclusion, increasing quartiles of serum uric acid was associated with 10-year incidence of hypertension independent of smoking, alcohol intake and baseline kidney function suggesting an independent positive association between serum uric acid levels and hypertension development among community-dwelling older adults.

Serum uric acid and long-term mortality from stroke, coronary heart disease and all causes

BACKGROUND

Increased serum uric acid (SUA) levels are linked to obesity, dyslipidemia, diabetes and hypertension. Whether SUA carries a risk for coronary heart disease (CHD) and stroke remains uncertain.

DESIGN

A prospective cohort study.

METHODS

Of an original cohort of middle-aged workers who were examined in 1963 and followed-up for 23 years, 9125 men, free of CHD at entry, are included in this study. Subjects were divided into quintiles according to baseline SUA levels. Hazard ratios (HR) for all-cause, CHD, and stroke mortality were estimated in SUA quintiles, with the third serving as a referent.

RESULTS

During follow-up, 2893 deaths were recorded, including 830 ascribed to CHD and 292 to stroke. The HR for all death [1.22, 95% confidence interval (CI) 1.09-1.37] and CHD (1.29, 95% CI 1.05-1.58) were increased in the upper SUA quintile. Fatal stroke showed a U-shaped relationship as both the upper (HR 1.48, 95% CI 1.02-2.17) and bottom (HR 1.43, 95% CI 0.99-2.08) quintiles were associated with a higher risk. Adjustment for confounders reduced the HR of the upper quintile for all outcomes, but did not attenuate the association of the bottom quintile with stroke (HR 1.52, 95% CI 1.04-2.23). When analysed separately by stroke type, the latter association seemed to be stronger for hemorrhagic (HR 3.27, 95% CI 1.14-9.33) than for ischemic stroke (HR 1.34, 95% CI 0.87-2.05).

CONCLUSION

In addition to findings supporting increased mortality among hyperuricemic subjects, we identified an association between low SUA levels and fatal stroke, which deserves further investigation.

Elevated serum uric acid levels in metabolic syndrome: an active component or an innocent bystander?

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.

Lupeol and its ester inhibit alteration of myocardial permeability in cyclophosphamide administered rats

Cyclophosphamide (CP), an alkylating agent widely used in cancer chemotherapy causes cardiac membrane damage. Lupeol, a pentacyclic triterpene, isolated from Crataeva nurvala stem bark and its ester, lupeol linoleate possess a wide range of medicinal properties. The effect of lupeol and its ester was evaluated in CP induced alterations in cardiac electrolytes in rats. Male albino rats of Wistar strain were categorized into 6 groups. Group I served as control. Rats in groups II, V and VI were injected intraperitoneally with a single dose of CP (200 mg/kg body weight) dissolved in saline. CP treated groups V and VI received lupeol and lupeol linoleate (50 mg/kg body weight) respectively, dissolved in olive oil for 10 days by oral gavage. At the end of the experimental period, urinary risk factors, activities of ATPases and electrolytes were measured using standard procedures. CP administered rats showed a significant decrease (P < 0.001) in the activities of ATPases. It was associated with significant alterations (P < 0.001) of electrolytes both in serum and cardiac tissue. The levels of urea, uric acid and creatinine were also significantly (P < 0.001) altered in the serum and urine. Lupeol and its ester showed reversal of the above alterations induced by CP. These findings demonstrate that the supplementation with lupeol and its ester could preserve membrane permeability, highlighting their protective effect against CP induced cardiotoxicity.

Longevity-associated NADH dehydrogenase subunit-2 237 Leu/Met polymorphism influences the effects of alcohol consumption on serum uric acid levels in nonobese Japanese men

NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is reportedly associated with longevity in the Japanese population. The ND2-237Met genotype may confer resistance to cardiovascular and cerebrovascular atherogenic diseases. Hyperuricemia is one of the risk factors for cardiovascular disease. To investigate whether ND2-237 Leu/Met polymorphism is associated with serum uric acid (SUA) levels, we conducted a cross-sectional study in 321 healthy Japanese male subjects. In nonobese (body mass index, BMI<25) male subjects, interaction between ND2-237 Leu/Met genotypes and drinking frequency on SUA levels was observed (P=0.031). The SUA levels were significantly higher in daily drinkers with ND2-237Leu than in non-daily drinkers with ND2-237Leu (P=0.018). In nonobese men, after adjustment for covariates, daily drinkers with ND2-237Leu had a significantly higher odds ratio (OR) for hyperuricemia (SUA> or =6.5 mg/dl: vs. daily drinkers with ND2-237Met, OR=3.26, 95% confidence interval (CI) 1.14-9.29; vs. non-daily drinkers with ND2-237Leu, OR=3.22, 95% CI 1.39-7.45; SUA> or =7.0 mg/dl: vs. non-daily drinkers with ND2-237Met, OR=3.53, 95% CI 1.00-12.4). However, in obese (BMI> or =25) men, no significant interaction between ND2-237 Leu/Met polymorphism and habitual drinking on SUA levels or on the risk for hyperuricemia was observed. These results suggest that ND2-237 Leu/Met polymorphism modulates the effects of daily alcohol consumption on SUA levels in nonobese Japanese men.

Ankle-arm index is a useful test for clinical practice in outpatients with suspected coronary artery disease

BACKGROUND

Although a low ankle-arm index (AAI) has been reported to be associated with increased risk of cardiovascular mortality in several populations, no data exist concerning the impact of AAI for outpatients with suspected coronary artery disease (CAD) in the clinical setting.

METHODS AND RESULTS

The present study enrolled 840 outpatients (age range 35-87 years, mean age 63.9+/-10.2) with suspected CAD. All patients underwent AAI measurements and coronary angiography, and based on the AAI values, they were divided into group A (AAI <0.9; n=191; CAD positive, 181) and group B (AAI >or=0.9; n=649; CAD positive, 509). Metabolic syndrome (MS), obesity, and level of the inflammatory biomarker high sensitive C-reactive protein (hsCRP) were compared between the 2 groups. The sensitivity, specificity, positive and negative predictive values in predicting CAD with an AAI value <0.9 in all patients were 26.2%, 93.3%, 94.8% and 21.6%, respectively. The patients in group A was significantly older and there was a higher female-to-male ratio than in group B. The presence of hypertension and diabetes mellitus, current smoking status, and levels of low density lipoprotein (LDL)-cholesterol level, uric acid and hsCRP differed significantly between the 2 groups. Group A had a higher percentage of high LDL-cholesterol level, high waist-to-hip ratio and more positive cases of MS than group B. Multivariate logistical regression analysis showed that AAI was related to MS, high levels of hsCRP (>3 mg/L) and uric acid (>7 mg/dl) with odds ratios of 1.769, 3.907 and 2.580, respectively.

CONCLUSIONS

The AAI test is an effective tool in predicting CAD in outpatients in clinical practise.

Therapeutic effects of xanthine oxidase inhibitors: renaissance half a century after the discovery of allopurinol

The prototypical xanthine oxidase (XO) inhibitor allopurinol, has been the cornerstone of the clinical management of gout and conditions associated with hyperuricemia for several decades. More recent data indicate that XO also plays an important role in various forms of ischemic and other types of tissue and vascular injuries, inflammatory diseases, and chronic heart failure. Allopurinol and its active metabolite oxypurinol showed considerable promise in the treatment of these conditions both in experimental animals and in small-scale human clinical trials. Although some of the beneficial effects of these compounds may be unrelated to the inhibition of the XO, the encouraging findings rekindled significant interest in the development of additional, novel series of XO inhibitors for various therapeutic indications. Here we present a critical overview of the effects of XO inhibitors in various pathophysiological conditions and also review the various emerging therapeutic strategies offered by this approach.

Possible interactions of the endothelial constitutive nitric oxide synthase genotype with alcohol drinking and walking time for high serum uric acid levels among Japanese

A variable number of tandem repeat polymorphism located in intron 4 of the gene for endothelial constitutive nitric oxide synthase (ecNOS) is reported to be significantly associated with the nitric oxide level, which influences serum uric acid (SUA). To cast light on any association between the polymorphism and hyperuricemia, as well as gene-environment interactions, a cross-sectional study was conducted for 703 health checkup examinees (213 men and 490 women). The age-adjusted odds ratio (aOR) of hyperuricemia (> or =7 mg/dL) for ecNOS 4/4, 4/5, or 5/6 genotypes (non-5/5 group) as compared with the 5/5 genotype was 2.41 (95% confidence interval [CI], 1.09-5.30) in men. The aORs for drinking alcohol relative to never drinking were found to be 8.93 (95% CI, 1.02-78.16) among men with non-5/5 genotypes and 1.76 (95% CI, 0.59-5.26) for their 5/5 counterparts. Moreover, the aORs for heavy drinking (> or =50 mL/d) were 23.16 (95% CI, 2.14-250.35) and 2.48 (95% CI, 0.75-8.15), respectively. The interaction between the genotype and current drinking was 3.10 (95% CI, 0.45-21.41). The aORs for more than 30 minutes of daily walking relative to 30 minutes or less of daily walking were found to be 1.54 (95% CI, 0.40-5.95) among men with non-5/5 genotypes and 0.31 (95% CI, 0.12-0.81) for their 5/5 counterparts. The interaction between the genotype and more than 30 minutes of daily walking was 4.92 (95% CI, 0.95-25.64). This study indicated that the ecNOS variable number of tandem repeat polymorphism influences the SUA level in men. Although the interactions were not significant, alcohol intake may be more influential among men with non-5/5 genotypes and walking may be more effective among men with the 5/5 genotype. These findings would be informative for men with high SUA levels.

Possible pathophysiologic mechanisms supporting the superior stroke protection of angiotensin receptor blockers compared to angiotensin-converting enzyme inhibitors: clinical and experimental evidence

Stroke is a major cause of death and disability and its incidence increases linearly with age and the level of systolic and diastolic blood pressure. Stroke, besides being a cause of long-term disability for the affected person, also imposes a significant burden on society and healthcare costs. Although good blood pressure control is very critical for stroke prevention, angiotensin receptor blockers (ARBs) may be superior to angiotensin-converting enzyme inhibitors (ACEIs) for the same degree of blood pressure control. This hypothesis has clinical and experimental support. ARBs prevent stroke incidence by blocking the angiotensin II (AII), AT1 receptors preventing brain ischaemia and allowing AII to stimulate the unoccupied AT2 receptors, which improve brain ischaemia. ACEIs, by reducing AII generation, are less effective in preventing stroke. This hypothesis provides evidence that AII plays an important role in the prevention of stroke. Certain ARBs like losartan, and telmisartan, irbesartan and candesartan possess additional properties which may play a role in stroke prevention, which is independent of AII. These include antiplatelet aggregating, hypouricemic, antidiabetic and atrial antifibrillatory effects. However, the most critical factor in stroke prevention is good blood pressure control irrespective of drug used.

Treatment of systolic hypertension: spotlight on recent studies with angiotensin II antagonists

Systolic blood pressure has a continuous, graded, strong, independent, and aetiologically significant relationship to mortality from coronary heart disease, stroke, and all cardiovascular diseases, as well as to all-cause mortality and life expectancy. Angiotensin II (AII) may be intimately involved in the pathogenesis of systolic hypertension through multiple mechanisms, including decreasing the elastin content and increasing the collagen content of the arterial wall, thickening and fibrotic remodelling of the vascular intima, and proliferating smooth muscle cells in the arterial wall, resulting in increased thickness, stiffening, and partial loss of contractility. AII antagonists may therefore offer hitherto unrecognized benefits (independent of blood pressure) on age-related vascular damage and provide particular benefits in patients with systolic hypertension. Recent evidence has demonstrated that losartan offers cardiovascular outcomes benefits in isolated systolic hypertension (ISH) associated with an excellent tolerability profile. This, in patients with ISH, AII antagonists more facilitate systolic BP control, providing cardiovascular protection and offering an excellent risk-benefit profile.

Drug interactions with angiotensin receptor blockers

Many patients with high blood pressure receive multiple medications for hypertension and other conditions, placing them at risk for adverse drug interactions. Additionally, as the prevalence of hypertension increases with age, factors like greater frailty, comorbidity of the elderly requiring polypharmacy, and reduced hepatic and renal clearance rates for the elimination of drugs increase the likelihood of drug interactions. Angiotensin receptor blockers (ARBs) are the most recent class of agents for the treatment of hypertension. Due to a favourable side effect profile, this class of drugs deserves increased attention. This article reviews drug interactions of ARBs and suggests measures for reducing the risk of adverse events when drugs are co-administered. MEDLINE, EMBASE, Cochrane library, and CINAHL were searched. Reported and likely clinical relevant interactions of ARBs with concomitantly given drugs are summarised in Table 2 and 3. Compared to other classes of antihypertensive agents, the ARBs appear to have a low potential for drug interactions; however, interactions with this class occur and variations within the class have been detected, mainly due to different affinities for cytochrome P450 isoenzymes.

Relation of serum uric acid with metabolic risk factors in asymptomatic middle-aged Brazilian men

This study in 352 asymptomatic middle-aged Brazilian men demonstrated that serum uric acid increases linearly with an increasing number (0 to >/=3) of metabolic risk factors (5.78 +/- 1.1, 6.14 +/- 1.0, 6.27 +/- 1.1, and 6.79 +/- 1.3, p <0.001). In patients who had >/=3 metabolic risk factors, there was a higher prevalence of serum uric acid in the highest quartile (7.2 to 10.3 mg/dl) than in the lowest quartile (2.6 to 5.4 mg/dl, 35% vs 12%, p <0.001). Mean serum levels of uric acid were higher in those who had an abnormal ratio of >/=3 for triglyceride to high-density lipoprotein (suggesting insulin resistance) than in those who had a normal ratio (6.6 +/- 1.2 vs 5.87 +/- 1 mg/dl, p <0.001).

Serum uric acid and target organ damage in primary hypertension

The role of serum uric acid as an independent risk factor for cardiovascular and renal morbidity is controversial. A better understanding of its relationship with preclinical organ damage may help clarify the mechanism(s) implicated in the development of early cardiovascular disease. We evaluated the association between uric acid and the presence and degree of target organ damage in 425 (265 males, 160 females) middle-aged, untreated patients with essential hypertension. Left ventricular mass index and carotid intima-media thickness were assessed by ultrasound scan. Albuminuria was measured as the albumin to creatinine ratio in 3 nonconsecutive first morning urine samples. Overall, patients with target organ damage had significantly higher levels of serum uric acid as compared with those without it (presence versus absence of left ventricular hypertrophy, P=0.04; carotid abnormalities, P<0.05; microalbuminuria, P<0.004; and at least 1 versus no organ damage, P<0.03). In women, the occurrence and severity of each target organ damage we examined increased progressively from the lower to the upper serum uric acid tertiles (P<0.01). After adjustment for body mass index, age, creatinine clearance, and high-density lipoprotein cholesterol, each standard deviation increase in serum uric acid entailed a 75% higher risk of having cardiac hypertrophy and a 2-times greater risk of having carotid abnormalities. These results support the role of serum uric acid as an independent, modifiable marker of cardiovascular damage.

{alpha}-Tocopherol disappearance is faster in cigarette smokers and is inversely related to their ascorbic acid status

BACKGROUND

Cigarette smokers have enhanced oxidative stress from cigarette smoke exposure and from their increased inflammatory responses.

OBJECTIVE

The objective of this study was to determine whether cigarette smoking increases plasma alpha-tocopherol disappearance in otherwise healthy humans.

DESIGN

Smokers and nonsmokers (n = 10/group) were supplemented with deuterium-labeled alpha-tocopheryl acetates (75 mg each of d(3)-RRR-alpha-tocopheryl acetate and d(6)-all-rac-alpha-tocopherols acetate) for 6 evenings (days -6 to -1). Plasma alpha-tocopherols, ascorbic acid, uric acid, and F(2alpha)-isoprostanes were measured in blood samples collected on days -6 through 17. The urinary alpha-tocopherol metabolite, alpha-carboxy-ethyl-hydroxy-chroman (alpha-CEHC), was measured on days -6, 0, and 17 in 24-h urine samples.

RESULTS

F(2alpha)-isoprostanes were, on average, approximately 40% higher in smokers than in nonsmokers. On day 0, plasma labeled and unlabeled alpha-tocopherol concentrations were not significantly different between groups. Smoking resulted in faster fractional disappearance of plasma alpha-tocopherol (0.215 +/- 0.011 compared with 0.191 +/- 0.009 pools/d; P < 0.05). Fractional disappearance rates of alpha-tocopherol correlated with plasma ascorbic acid concentrations in smokers (P = 0.021) but not in nonsmokers despite plasma ascorbic acid concentrations that were not significantly different between groups. By day 17, cigarette smoking resulted in lower plasma alpha-tocopherol concentrations and urinary excretion of labeled and unlabeled alpha-CEHC (P < 0.05).

CONCLUSIONS

Cigarette smoking increased alpha-tocopherol disappearance. Greater rates of alpha-tocopherol disappearance in smokers appear to be related to increased oxidative stress accompanied by lower plasma ascorbic acid concentrations. Thus, smokers have an increased requirement for both alpha-tocopherol and ascorbic acid.

Chronic Treatment With Allopurinol Boosts Survival and Cardiac Contractility in Murine Postischemic Cardiomyopathy

Oxidative stress is a hallmark of systemic illnesses, including heart failure. Nevertheless, the overall importance of radical production in the heart remains conjectural; is it merely a marker of illness, or can intervention alter the progression of disease? This question was addressed by blocking xanthine oxidase (XO), a superoxide-generating enzyme that is upregulated in animal models of heart failure. In a randomized prospective trial design, we administered the XO inhibitor allopurinol orally to mice that had undergone massive myocardial infarction (MI). Cardiac XO activity was elevated in untreated mice after MI; allopurinol suppressed the XO activity to levels comparable to those in sham-operated mice. Eighty-one percent of untreated mice died of advanced heart failure over 2 to 4 weeks of follow-up. Survival doubled in the allopurinol-treated mice, whereas cardiac contractile function (both in vivo and in isolated muscle) was markedly improved. Response to isoproterenol was restored to near-normal levels in the allopurinol group but was attenuated in untreated mice. Oxidative modifications to proteins were prevented in the allopurinol-treated mice. Our findings indicate that targeted blockade of just one source of oxidants, XO, impacts dramatically on the progression of postischemic cardiomyopathy in mice and prevents oxidative protein modifications.

Xanthine oxidoreductase is an endogenous regulator of cyclooxygenase-2

Xanthine oxidoreductase (XOR) is the enzyme responsible for the final step in purine degradation resulting in the generation of uric acid. Here we have generated mice deficient in XOR. As expected, these animals lack tissue XOR activity and have low to undetectable serum levels of uric acid. Although normal at birth, XOR-/- mice fail to thrive after 10 to 14 days, and most die within the first month. The cause of death appears to be a form of severe renal dysplasia, a phenotype that closely resembles what has been observed previously in cyclooxygenase-2 (COX-2)-deficient mice. We further demonstrate that in the first month of life, a period in which the mouse kidney is undergoing rapid maturation and remodeling, wild-type mice exhibit an approximately 30-fold increase in renal XOR activity, with a corresponding induction of COX-2 expression. In contrast, during this same period, XOR-/- animals fail to augment renal COX-2 expression. Finally, we show that in vitro and in vivo, uric acid can stimulate basal COX-2 expression. These results demonstrate that XOR activity is an endogenous physiological regulator of COX-2 expression and thereby provide insight into previous epidemiological evidence linking elevated serum uric levels with systemic hypertension and increased mortality from cardiovascular diseases. In addition, these results suggest a novel molecular link between cellular injury and the inflammatory response.

The role of angiotensin antagonism in stroke prevention in patients with hypertension: focus on losartan

Optimal management of hypertension has been shown to reduce the risk of stroke. In recent years, newer classes of antihypertensive such as the angiotensin II (Ang II) antagonists have become available. Results from the Losartan Intervention for Endpoint reduction in hypertension (LIFE) study suggest the utility of this particular Ang II antagonist in stroke prevention. Treatment with a losartan-based regimen or an atenolol-based regimen produced similar reductions in blood pressure during almost 5 years of follow up. Losartan, however, reduced the risk of stroke by 25% compared with atenolol (p = 0.001). For a subgroup of patients with isolated systolic hypertension, losartan reduced the risk of stroke by 40% (p = 0.02). As well as blocking the Ang II type 1 receptor, losartan also acts as an antagonist at the thromboxane A2 receptor and has uricosuric effects, which may provide additional mechanisms by which losartan provides protective benefits beyond its antihypertensive action. The relevance of these molecular properties of losartan over other Ang II antagonists is further supported by comparison of the outcomes obtained in clinical trials employing two other Ang II antagonists, valsartan and candesartan.

Uric acid: A new look at an old risk marker for cardiovascular disease, metabolic syndrome, and type 2 diabetes mellitus: The urate redox shuttle

Background

The topical role of uric acid and its relation to cardiovascular disease, renal disease, and hypertension is rapidly evolving. Its important role both historically and currently in the clinical clustering phenomenon of the metabolic syndrome (MS), type 2 diabetes mellitus (T2DM), atheroscleropathy, and non-diabetic atherosclerosis is of great importance.

Results

Uric acid is a marker of risk and it remains controversial as to its importance as a risk factor (causative role). In this review we will attempt to justify its important role as one of the many risk factors in the development of accelerated atherosclerosis and discuss its importance of being one of the multiple injurious stimuli to the endothelium, the arterial vessel wall, and capillaries. The role of uric acid, oxidative – redox stress, reactive oxygen species, and decreased endothelial nitric oxide and endothelial dysfunction cannot be over emphasized.

In the atherosclerotic prooxidative environmental milieu the original antioxidant properties of uric acid paradoxically becomes prooxidant, thus contributing to the oxidation of lipoproteins within atherosclerotic plaques, regardless of their origins in the MS, T2DM, accelerated atherosclerosis (atheroscleropathy), or non-diabetic vulnerable atherosclerotic plaques. In this milieu there exists an antioxidant – prooxidant urate redox shuttle.

Conclusion

Elevations of uric acid > 4 mg/dl should be considered a "red flag" in those patients at risk for cardiovascular disease and should alert the clinician to strive to utilize a global risk reduction program in a team effort to reduce the complications of the atherogenic process resulting in the morbid – mortal outcomes of cardiovascular disease.

Uric acid levels and vascular disease

There is evidence showing that serum uric acid (SUA) levels predict the risk for vascular events. For example, up to 29% of the reduction in the primary composite endpoint seen in the LIFE trial (favouring losartan versus atenolol) can be attributed to a fall in SUA levels. We also discuss the findings of the GREACE study (treating to target with atorvastatin versus 'usual' care) in relation to SUA levels. In this brief comment we extend this argument to consider the SUA-lowering effect of other drugs commonly prescribed in patients with vascular disease (e.g. statins, fibrates and antihypertensive agents). A judicious use of drugs (alone or in combination) will result in small reductions in SUA levels. These changes may translate into a substantial reduction in the risk of vascular events. Results retrieved from completed trials together with new prospective findings will support or refute the proposed association between lowering SUA levels and reducing vascular morbidity and mortality.