Relation between serum uric acid and lower limb blood flow in patients with chronic heart failure

Association of serum uric acid change with mortality, renal function and diuretic dose administered in treatment of acute heart failure

BACKGROUND AND AIMS

Hyperuricemia is reportedly associated with poor outcome in acute heart failure (AHF). The association between changes in Uric acid (UA) levels with renal function change, diuretic doses, and mortality in patients with AHF were studied.

METHODS AND RESULTS

Consecutive patients hospitalized with AHF were reviewed (n = 535). UA levels were measured at admission and either at discharge or on approximately the seventh day of admission. Patients with an UA change in the top tertile were defined as having an increase (UA-increase) and were compared to those outside the top tertile (non-UA-increase). The endpoint was all-cause mortality, with a mean follow-up duration of 22.2 months. Patients in the UA-increase group presented with greater creatine increase (P < 0.001), and were administered a higher average daily dose of loop diuretic (P = 0.016) compared with the non-UA-increase group. In-hospital UA-increase was associated with higher risk of mortality even after adjusting for confounding variables including creatine change and diuretic dosage [harzard ratio (HR) 1.53, 95% confidence interval (CI) 1.02-2.30, P = 0.042]. In patients with hyperuricemia on admission, UA-increase was associated with increased mortality (adjusted HR 2.21, 95% CI 1.38-3.52, P = 0.001). Whereas, in those without admission hyperuricemia, UA-increase had no significant association with mortality.

CONCLUSIONS

An increase in UA during in-hospital treatment is associated with an increase in creatine levels and daily diuretic dose. Mortality associated with increased UA is restricted to patients who already have hyperuricemia at admission. A combination of UA levels at admission and UA changes on serial assessment during hospitalization may be additional value in the risk stratification of AHF patients.

Association of diabetes mellitus with decline in ankle-brachial index among patients on hemodialysis: A 6-year follow-up study

Peripheral artery occlusive disease is common among diabetes mellitus (DM) and end-stage renal disease patients, and tends to progress faster and lead to worse outcomes. This study compared the association of DM with the decline in ankle-brachial index (ABI) among patients on hemodialysis (HD). This was a longitudinal analysis of ABI in HD patients from 2009 to 2015. Medical records and yearly ABI values were obtained. A longitudinal mixed-model analysis was used to evaluate ABI changing trends while accounting for within-patients correlation. There were 296 patients on HD in the period of 2009-2015. In a 6-year follow-up, those with DM had a more rapid ABI decline compared to non-DM patients (slopes: -0.014 vs. 0.010 per year, interaction p < 0.001). In DM patients, female sex, high pulse pressure, high triglyceride, low creatinine, and high uric acid were associated with a decrease in ABI. In non-DM patients, old age, high pulse pressure, high low-density lipoprotein cholesterol, and high uric acid were associated with a decreased in ABI. There were 49.6% of patients with a normal ABI experienced a decrease at least 0.1 of ABI from baseline, and 35.3% had a final ABI < 0.9 in patients with a baseline ABI ≥ 0.9 (n = 232). In this study, DM patients on HD tend to develop a more rapid decline in ABI than non-DM patients on HD. Age, sex, pulse pressure, lipid profile, creatinine, and uric acid are associated with a decreased in ABI.

Asymptomatic hyperuricemia is independently associated with coronary artery calcification in the absence of overt coronary artery disease: A single-center cross-sectional study

Recently, the pathogenic role of uric acid (UA) in both systemic metabolic and atherosclerotic diseases has been investigated. We sought to determine the independent correlation between serum UA levels and coronary artery calcification, as a marker of subclinical atherosclerosis. A total of 4188 individuals without prior coronary artery disease or urate-deposition disease were included. All of the participants underwent multidetector computed tomography (MDCT) for the evaluation of coronary artery calcification (CAC) during their health check-ups. The subjects were divided into thre groups according to CAC scores (group 1: 0; group 2: 1-299; group 3: ≥300). After controlling for other confounders, serum UA levels were found to be positively associated with increasing CAC scores (P = 0.001). Adjusted mean serum UA levels in each CAC group were estimated to be 5.2 ± 0.1 mg/dL, 5.3 ± 0.1 mg/dL, and 5.6 ± 0.2 mg/dL from groups 1, 2, and 3, respectively. Subsequent subgroup analyses revealed that this positive association was only significant in participants who were male, relatively older, less overweight, and did not have diabetes mellitus (DM), hypertension, smoking history, or renal dysfunction. In conclusion, serum uric acid levels were independently associated with CAC score severity and this finding is particularly relevant to the subjects who were male, relatively older, less overweight (body mass index < 25 kg/m), and without a history of DM, hypertension, smoking, or renal dysfunction.

Xanthine oxidase inhibition for the treatment of cardiovascular disease: an updated systematic review and meta-analysis

Background

Previous studies have shown that xanthine oxidase inhibitors (XOI) might improve outcome for patients with cardiovascular disease. However, more evidence is required.

Methods and results

We published a meta‐analysis of trials conducted before 2014 examining the effects of XOI on mortality in patients with cardiovascular disease. At least two further trials (N = 323 patients) have since been published. Accordingly, we repeated our analysis after a further search for randomized controlled trials of XOI in PubMed/MEDLINE, EMBASE, and Cochrane Databases. We identified eight relevant trials with 1031 patients. The average age of the patients was 61 years and 68% were men (one study did not report gender). There were 57 deaths in these eight trials, 26 in those assigned to XOI, and 31 in those assigned to the control. The updated meta‐analysis could not confirm a reduction in mortality for patients assigned to XOI compared with placebo (odds ratio 0.84) but 95% confidence intervals were wide (0.48–1.47).

Conclusions

This updated meta‐analysis does not suggest that XOI exert a large reduction in mortality but also cannot exclude the possibility of substantial harm or benefit.

Prednisone lowers serum uric acid levels in patients with decompensated heart failure by increasing renal uric acid clearance

Clinical studies have shown that large doses of prednisone could lower serum uric acid (SUA) in patients with decompensated heart failure (HF); however, the optimal dose of prednisone and underlying mechanisms are unknown. Thirty-eight patients with decompensated HF were randomized to receive standard HF care alone (n = 10) or with low-dose (15 mg/day, n = 8), medium-dose (30 mg/day, n = 10), or high-dose prednisone (60 mg/day, n = 10), for 10 days. At the end of the study, only high-dose prednisone significantly reduced SUA, whereas low- and medium-dose prednisone and standard HF care had no effect on SUA. The reduction in SUA in high-dose prednisone groups was associated with a significant increase in renal uric acid clearance. In conclusion, prednisone can reduce SUA levels by increasing renal uric acid clearance in patients with decompensated HF.

Association of Far-Infrared Radiation Therapy and Ankle-Brachial Index of Patients on Hemodialysis with Peripheral Artery Occlusive Disease

Background and Aim: The ankle-brachial index (ABI) is recognized to be a good marker for atherosclerosis, and is useful in the diagnosis of peripheral artery occlusive disease (PAOD) which is prevalent among patients on hemodialysis (HD). Methods: This randomized trial aimed to evaluate the effect of far-infrared radiation (FIR) therapy on ABI in HD patients with PAOD. PAOD was defined as patients with ABI < 0.95. One hundred and eight HD patients were enrolled, including 50 in the control group and 58 in the FIR group. A WS TY101 FIR emitter was applied for 40 minutes during each HD session, three times per week for six months. The ABI was measured before and after the FIR therapy. Results: Regardless of FIR therapy, the bilateral ABI decreased (in the FIR group, left: 0.88±0.22 to 0.85±0.24, p = 0.188; right: 0.92±0.20 to 0.90±0.23, p = 0.372; in control group, left: 0.91±0.23 to 0.88±0.21, p = 0144; right: 0.93±0.17 to 0.89±0.21, p = 0.082). Multivariate logistic analysis of the FIR group revealed that high uric acid (odds ratio [OR]: 2.335; 95% confidence interval [CI]: 1.117-4.882; p=0.024) and aspirin use (OR: 16.463; 95% CI: 1.787-151.638; p=0.013) were independently associated with increased bilateral ABI after FIR therapy. Conclusions: This study demonstrates that ABI is not increased after FIR therapy in HD patients with PAOD. However, in the FIR group, patients with higher uric acid level or those who used aspirin have increased bilateral ABI after FIR therapy.

Relation of serum uric acid to cardiovascular disease

This review summarizes recent published literature on the association between serum uric acid and cardiovascular disease, a relationship which is complex and not fully elucidated. Uric acid may be a marker for risk, a causative agent in cardiovascular disease, or both. Various biologic factors can influence serum uric acid levels, and serum uric acid level itself is closely related to conditions such as hypertension, dyslipidemia, obesity, and impaired glucose metabolism, that contribute to cardiovascular disease pathophysiology. Serum uric acid levels have been found to be associated with adverse outcomes, including mortality, in the general population. In addition, serum uric acid is associated with increased risk for incident coronary heart disease, heart failure, and atrial fibrillation. In the setting of established systolic heart failure, serum uric acid is positively associated with disease severity and mortality risk. Whether targeting treatment based on uric acid levels might affect clinical outcomes is still being studied.

Hyperuricemia: An Early Marker for Severity of Illness in Sepsis

Background. Uric acid can acutely activate various inflammatory transcription factors. Since high levels of oxyradicals and lower antioxidant levels in septic patients are believed to result in multiorgan failure, uric acid levels could be used as a marker of oxidative stress and poor prognosis in patients with sepsis. Design. We conducted a prospective cohort study on Medical Intensive Care Unit (MICU) patients and hypothesized that elevated uric acid in patients with sepsis is predictive of greater morbidity. The primary end point was the correlation between hyperuricemia and the morbidity rate. Secondary end points were Acute Kidney Injury (AKI), mortality, Acute Respiratory Distress Syndrome (ARDS), and duration of stay. Results. We enrolled 144 patients. 54 (37.5%) had the primary end point of hyperuricemia. The overall morbidity rate was 85.2%. The probability of having hyperuricemia along with AKI was 68.5% and without AKI was 31.5%. Meanwhile the probability of having a uric acid value <7 mg/dL along with AKI was 18.9% and without AKI was 81.1% (p value < 0.0001). Conclusion. We report that elevated uric acid levels on arrival to the MICU in patients with sepsis are associated with poor prognosis. These patients are at an increased risk for AKI and ARDS.

Predictors of Chronic Total Occlusion in Nonculprit Artery in Patients With Acute Coronary Syndrome

Chronic total occlusion (CTO) in a noninfarct-related artery (non-IRA) is an independent predictor of mortality in acute coronary syndrome (ACS). Mean platelet volume (MPV) and serum uric acid (SUA) are associated with cardiovascular events in ACS. We investigated the relationship between the presence of non-IRA-CTO with MPV and SUA levels in patients with ACS. Patients (n = 1024) who underwent urgent coronary angiography for ACS were included in this study. Blood samples were drawn on admission. Patients were categorized into 2 groups: non-IRA-CTO (−) and non-IRA-CTO (+). The MPV and SUA levels on admission were significantly higher in the non-IRA-CTO (+) group than in the non-IRA-CTO (−) group ( P < .001). At multivariate analysis, MPV (odds ratio [OR]: 4.705, P < .001) and SUA (OR: 2.535, P < .001) were independent predictors of non-IRA-CTO together with age, hemoglobin, ejection fraction, and non-ST-segment elevation ACS. The MPV and SUA levels were significant and independent predictors for the presence of non-IRA-CTO in patients with ACS.

Relationship of serum uric Acid level and angiographic severity of coronary artery disease in male patients with acute coronary syndrome

Background and objective: The association between serum uric acid and ischemic heart disease remains controversial and it has not yet been established as cardiovascular risk factor. Our objective was to study the association of serum uric acid level with angiographic severity of coronary artery disease in men with acute coronary syndrome (ACS).

Methods: This cross-sectional study was conducted on 100 consecutive male patients presenting with ACS at Punjab Institute of Cardiology. Hyperuricemia was defined as serum uric acid level > 6.5 mg/dl. Severity of ischemic heart disease was assessed on the basis of Gensini score, number of diseased vessels, critical lesions and total occlusions on coronary angiogram.

Results: Mean age of normouricemic group (n=59) was 52.62 ± 9.46 years and mean age of hyperuricemic group (n=41) was 50.52 ± 9.40 years (p=0.273). Mean uric acid level; normouricemic group (4.75 ± 1.05), hyperuricemic group (7.61 ± 1.24), p<0.001. Mean Gensini score; normouricemic group (22.15 ± 21.52), hyperuricemic group (35.69 ± 26.80). Mann Whitney U test was applied to compare the Gensini score of two groups and it showed statistically significant difference (p value <0.006). Critical lesions, total occlusions and multi-vessel disease were more frequent in hyperuricemic group but statistically significant difference was found only for total occlusions (p=0.013) and critical lesions (p=0.046).

Conclusions: Hyeruricemia is associated with higher Gensini score and more frequent total occlusions and critical lesions in men presenting with acute coronary syndrome.

Pregnancy and hemolysis, elevated liver enzymes and low platelet count syndrome in patients with Eisenmenger's syndrome

Eisenmenger's syndrome is characterized by a right-to-left or bidirectional shunt in congenital heart diseases. Hemolysis, elevated liver enzymes and low platelet count (HELLP) syndrome, commonly occurring during pregnancy, includes hemolysis, elevated liver enzymes and low platelet counts. HELLP syndrome and pregnancy are extremely rare in patients with Eisenmenger's syndrome. The authors report 4 cases of pregnancy complicated by the HELLP and Eisenmenger's syndrome and describe their initial intervention and the in-hospital outcomes of these cases. Special emphasis is given to elaborate about the hemodynamic monitoring, magnesium sulphate for convulsions, corticosteroid treatment, anticoagulation therapy, management of pulmonary hypertension, the timing of delivery, and blood product transfusion.

Serum uric acid as an index of impaired renal function in congestive heart failure

Background

Hyperuricemia is frequently present in patients with heart failure. Many pathological conditions, such as tissue ischemia, renal function impairment, cardiac function impairment, metabolic syndrome, and inflammatory status, may impact uric acid (UA) metabolism. This study was to assess their potential relations to UA metabolism in heart failure.

Methods

We retrospectively assessed clinical characteristics, echocardiological, renal, metabolic and inflammatory variables selected on the basis of previous evidence of their involvement in cardiovascular diseases and UA metabolism in a large cohort of randomly selected adults with congestive heart failure (n = 553). By clustering of indices, those variables were explored using factor analysis.

Results

In factor analysis, serum uric acid (SUA) formed part of a principal cluster of renal functional variables which included serum creatinine (SCr) and blood urea nitrogen (BUN). Univariate correlation coefficients between variables of patients with congestive heart failure showed that the strongest correlations for SUA were with BUN (r = 0.48, P < 0.001) and SCr (r = 0.47, P < 0.001).

Conclusions

There was an inverse relationship between SUA levels and measures of renal function in patients with congestive heart failure. The strong correlation between SUA and SCr and BUN levels suggests that elevated SUA concentrations reflect an impairment of renal function in heart failure.

Prognostic significance of serum uric acid in outpatients with chronic heart failure is complex and related to body mass index: data from the IN-CHF Registry

BACKGROUND AND AIMS

In the field of cardiovascular diseases, elevated levels of serum uric acid (UA) reflect a marked activation of the xanthine oxidase pathway with increase in free radicals production; it is often associated with an inflammatory state, oxygen consumption and endothelial dysfunction. All these associations have been also confirmed in heart failure (HF) but the pathophysiological role of UA in this setting is not well understood. The aim of this study was to evaluate the prognostic role of UA in outpatients enrolled in the Italian Registry of Congestive Heart Failure (IN-CHF).

METHODS AND RESULTS

All patients met the European Society of Cardiology (ESC) criteria for diagnosis of HF. We considered patients with complete clinical data and UA level available at the baseline and at 1-year follow-up. The study population was composed of 877 patients aged 63 ± 12 years. One-year mortality was 10.8% and dead patients had a higher level of UA than survivors (7.1 mg dl⁻¹ vs 6.6 mg dl⁻¹, p < 0.0207). In multivariable full model of analysis, UA did not result in an independent predictor of death in overall population, but only in patients with low body mass index (BMI) (≤22 kg m⁻²) (hazard ratio (HR): 2.38, 95% confidence interval (CI) 1.36-4.18). In this subgroup, a statistically significant gradual relationship between UA and survival was detected starting from values higher than 8 mg dl⁻¹.

CONCLUSION

Elevated level of UA is not an independent predictor of mortality in chronic HF, but it markedly worsens outcome if associated with low level of BMI. This association is likely an indicator of chronic inflammatory and catabolic state.

Gout and the risk for incident heart failure and systolic dysfunction

OBJECTIVE

To test the hypothesis that gouty arthritis (gout) is a risk factor for incidence of heart failure and for echocardiographic measures signifying subclinical heart failure.

DESIGN

Post-hoc, longitudinal and cross-sectional analyses of a prospective cohort study where data were collected in 4-year intervals since 1971.

SETTINGS

The population-based Framingham Offspring Study.

PARTICIPANTS

4989 adults (mean age 36 years, 52% women) free of clinical heart failure at baseline.

OUTCOME MEASURES

Incident heart failure, echocardiographic measures of left ventricular systolic dysfunction, dilatation and hypertrophy.

RESULTS

Participants with gout (n=228) had two to three times higher incidence of clinical heart failure and echocardiographic measures of systolic dysfunction compared with those without. In Cox regression analyses, gout was associated with an adjusted HR of 1.74 (95% CI 1.03 to 2.93) for incident heart failure and RRs of 3.70 (95% CI 1.68 to 8.16) for abnormally low left ventricular ejection fraction and of 3.60 (95% CI 1.80 to 7.72) for global left ventricle systolic dysfunction. These risk relationships were consistently observed in all clinical subgroups. Overall, participants with gout had greater mortality than those without (adjusted HR 1.58, 95% CI 1.40 to 1.78). Mortality was elevated in subgroup of patients with gout and heart failure (adjusted HR 1.50, 95% CI 1.30 to 1.73) compared to those with heart failure but without gout.

CONCLUSION

Gout is associated with increased risk for clinical heart failure, subclinical measures of systolic dysfunction and mortality.

High Levels of Serum Uric Acid Predict Severity of Coronary Artery Disease in Patients with Acute Coronary Syndrome

We aimed to elucidate the relation between serum uric acid (SUA) level and severity of coronary artery disease (CAD) in nondiabetic, nonhypertensive patients (n = 246) with acute coronary syndrome (ACS). Severity of CAD was assessed by the Gensini score. One, 2, and 3 or more diseased vessels were identified in 87 (35.4%), 55 (22.4%), and 104 (42.2%) patients, respectively. Patients with hyperuricemia had higher Gensini score, high number of diseased vessels, critical lesions, and total occlusion. Serum uric acid level was significantly associated with number of diseased vessels. Serum uric acid was an independent risk factor for multivessel disease by univariate analysis. High levels of SUA associated with the severity of CAD in nondiabetic, nonhypertensive patients with ACS.

Risk factors for development of diabetes mellitus, hypertension and dyslipidemia

We investigated the risk factors for the development of diabetes mellitus, hypertension and dyslipidemia simultaneously in a community-based observational cohort study (n=4304). When hypertension or dyslipidemia was present at baseline, hazard ratio (95% CI) of developing diabetes mellitus at year 5 is 3.014 (2.131-4.264) or 2.112 (1.520-2.936), respectively.

High Levels of Serum Uric Acid Impair Development of Coronary Collaterals in Patients With Acute Coronary Syndrome

We evaluated the association of serum uric acid (SUA) level and development of coronary collateral vessels (CCVs) in patients with acute coronary syndrome (ACS). Patients (n = 224) with ACS were included in the study. Coronary collateral vessels were graded according to the Rentrop scoring system. Rentrop grade 0 was accepted as absence of CCV (group 1; n = 117) and Rentrop grade ≥1 was accepted as presence of CCV (group 2; n = 107). Rentrop 0-1 (poor CCV) were determined in 167 patients and Rentrop 2-3 (good CCV) were determined in 57 patients. Both presence of CCV ( P < .001) and development of good CCV ( P = .003) were significantly associated with low levels of SUA. We suggest that high levels of SUA affect the CCV development negatively in nondiabetic and nonhypertensive patients with ACS.

The effects of a high-caloric protein-rich oral nutritional supplement in patients with chronic heart failure and cachexia on quality of life, body composition, and inflammation markers: a randomized, double-blind pilot study

The prevalence of cardiac cachexia in chronic heart failure is approximately 5% to 15% and 18-month mortality rates can reach 50%. Treatment with angiotensin-converting enzyme inhibitors and beta-blockers may confer some benefit but no proven therapy exists. We tested the effects of an oral nutritional supplement in cachectic patients with heart failure. This was a prospective, randomized, double-blind, placebo-controlled pilot study which randomized 29 patients to a high-caloric (600 kcal) high-protein (20 g) oral nutritional supplement or placebo for a duration of 6 weeks in addition to the patients' usual food intake. At baseline, 6 weeks, and 18 weeks, we measured body weight, quality of life, body composition, heart function, laboratory parameters, and exercise performance. Edema-free body weight increased in 19 of 20 patients receiving intervention at 6 weeks and in 17 of 19 patients at 18 weeks with an average weight gain of 2.0 ± 1.7 kg (3.1 ± 2.4%, p = 0.0001) and 2.3 ± 3.1 kg (3.6 ± 4.7%, p = 0.007) at 6 and 18 weeks, respectively. Most of the weight gain was fat tissue with an absolute gain of 1.5 ± 1.7 kg (p = 0.003) and 1.6 ± 2.7 kg (p = 0.008). A significant improvement in quality of life and decrease in serum levels of tumor necrosis factor-α were observed (p < 0.05 for both). We demonstrated the feasibility of oral nutritional supplement in cachectic patients with heart failure and significant clinical benefit in terms of body size and body composition, laboratory parameters, and quality of life (www.clinicaltrials.gov identifier NCT00654719).

Clinical value of serum uric Acid in patients with suspected coronary artery disease

BACKGROUND/AIMS

Although increased serum uric acid (SUA) concentrations are commonly encountered in patients with risk factors for coronary artery disease (CAD), the clinical value of SUA has not been established.

METHODS

The study group comprised 687 consecutive patients with suspected CAD who had undergone coronary angiography. CAD was defined as stenosis > or = 50% of the luminal diameter. CAD severity was expressed as 1-, 2-, or 3-vessel disease. Metabolic syndrome (MS) was defined according to National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) criteria, and aortofemoral pulse wave velocity (PWV) was obtained by arterial catheterization invasively.

RESULTS

In total, 395 patients had CAD. SUA was higher in patients with CAD as compared to those without CAD (5.5 +/- 1.0 vs. 5.2 +/- 1.0 mg/dL, p = 0.004). In addition, SUA was significantly associated with the severity of CAD (p = 0.002). However, after adjusting for significant confounding factors including age, diabetes, smoking, cholesterol, MS, and PWV, SUA was not an independent risk factor for CAD (p = 0.151). Based on a subgroup analysis, SUA was more closely associated with CAD in women than in men, and in the highest quartile (> or = 6.4 mg/dL) than in the first quartile (< 4.8 mg/dL); however, these results were not significant (p = 0.062, p = 0.075, respectively). In a multivariate regression analysis, the most important determinant of SUA was MS (i.e., insulin resistance syndrome), which is strongly associated with CAD.

CONCLUSIONS

In patients with suspected CAD, SUA was not an independent risk factor for CAD and may be merely a marker of insulin resistance.

Elevated serum uric acid levels following heart transplantation predict all-cause and cardiac mortality

AIMS

We evaluated the relationship between elevated serum uric acid (SUA) and mortality as well as cardiac allograft vasculopathy (CAV) among 184 heart transplant (HTx) recipients. We also measured inflammatory, neurohormonal, and oxidative stress markers to explore pathophysiological mechanisms.

METHODS AND RESULTS

There were 28 (15%) deaths, patients with SUA > or = 502 micromol/L (upper quartile) at 1 year post-HTx had an increased risk of total mortality (adjusted HR 2.21, P = 0.03) and cardiac mortality (adjusted HR 4.38, P = 0.03). Elevated SUA was a significant risk factor for development of moderate/severe angiographic CAV (adjusted HR 4.79, P = 0.01). A smaller decline in SUA (<97 micromol/L) during the first year post-HTx was also associated with an increased risk of mortality (P = 0.02). Patients with elevated SUA had significantly higher levels of high-sensitivity C-reactive protein (P = 0.008) and N-terminal probrain natriuretic peptide (P = 0.022), but there was no significant difference in oxidative stress parameters.

CONCLUSION

Elevated SUA at 1 year post-HTx, or a modest rather than a marked decline in SUA levels during the first year post-HTx, is associated with an increased risk of mortality. Although the pathophysiological mechanism is unclear, our data indicate a potential relationship between SUA and inflammation which should be explored further.

[Percutaneous aortic valve replacement - pro]

Percutaneous aortic valve replacement is presently on its way to revolutionize the current treatment practice for patients with degenerative aortic valve stenosis. Two different techniques are available: the balloon-expandable Edwards valve prosthesis and the self-expanding CoreValve ReValving prosthesis. After an initial learning curve as well as device modifications, use of the current generations has a > 95% success rate with a low peri- and post-interventional complication rate. In this article, an overview on the current status of this technique will be provided.

Oxidative stress and hyperuricaemia: pathophysiology, clinical relevance, and therapeutic implications in chronic heart failure

Heart failure (HF) is a state of chronic deterioration of oxidative mechanisms due to enhanced oxidative stress and consequent subcellular alterations. In this condition, oxidant-producing enzymes, in particular xanthine oxidase (XO), the major cardiovascular source of reactive oxygen species (ROS), are up-regulated. Growing evidence shows that this impaired oxidative metabolism due to enhanced ROS release is implicated in the development of cardiac hypertrophy, myocardial fibrosis, left ventricular remodelling, and contractility impairment responsible for worsening of cardiac function in CHF. Uric acid (UA) has long been linked with cardiovascular diseases, and hyperuricaemia is a common finding in patients with CHF. Hyperuricaemia is associated with impairment of peripheral blood flow and reduced vasodilator capacity, which relate closely to clinical status and reduced exercise capacity. Recent studies also suggest an association between UA levels and parameters of diastolic function; more importantly, UA has emerged as a strong independent prognostic factor in patients with CHF. In this review, we describe the up-to-date experimental and clinical studies that have begun to test whether the inhibition of XO translates into meaningful beneficial pathophysiological changes. This treatment gives evidence that myocardial energy, endothelial dysfunction, and vasodilator reactivity to exercise are improved by reducing markers of oxidative stress responsible for vascular dysfunction, so it represents an interesting therapeutic alternative for better outcome in CHF patients.

Association between hyperuricemia and incident heart failure among older adults: a propensity-matched study

BACKGROUND

The association between hyperuricemia and incident heart failure (HF) is relatively unknown.

METHODS

Of the 5461 community-dwelling older adults, >or=65 years, in the Cardiovascular Health Study without HF at baseline, 1505 had hyperuricemia (baseline serum uric acid >or=6 mg/dL for women and >or=7 mg/dL for men). Using propensity scores for hyperuricemia, estimated for each participant using 64 baseline covariates, we were able to match 1181 pairs of participants with and without hyperuricemia.

RESULTS

Incident HF occurred in 21% and 18% of participants respectively with and without hyperuricemia during 8.1 years of mean follow-up (hazard ratio {HR} for hyperuricemia versus no hyperuricemia, 1.30; 95% confidence interval {CI}, 1.05-1.60; P=0.015). The association between hyperuricemia and incident HF was significant only in subgroups with normal kidney function (HR, 1.23; 95% CI, 1.02-1.49; P=0.031), without hypertension (HR, 1.31; 95% CI, 1.03-1.66; P=0.030), not receiving thiazide diuretics (HR, 1.20; 95% CI, 1.01-1.42; P=0.044), and without hyperinsulinemia (HR, 1.35; 95% CI, 1.06-1.72; P=0.013). Used as a continuous variable, each 1 mg/dL increase in serum uric acid was associated with a 12% increase in incident HF (HR, 1.12; 95% CI, 1.03-1.22; P=0.006). Hyperuricemia had no association with acute myocardial infarction or all-cause mortality.

CONCLUSIONS

Hyperuricemia is associated with incident HF in community-dwelling older adults. Cumulative data from our subgroup analyses suggest that this association is only significant when hyperuricemia is a marker of increased xanthine oxidase activity but not when hyperuricemia is caused by impaired renal elimination of uric acid.

Hyperuricemia in acute heart failure. More than a simple spectator?

BACKGROUND

Hyperuricemia is a prevalent condition in chronic heart failure (CHF), describing increased oxidative stress and inflammation. Although there is evidence that serum uric acid (UA) predicts mortality in CHF, its role as a prognostic biomarker in acute heart failure (AHF) has not yet been well assessed. The aim of this study was to determine if UA levels predict all-cause mortality. Additionally, as a secondary endpoint we sought the clinical predictors of UA serum level in this population.

METHODS

We analyzed 560 consecutive patients with AHF admitted in a single university center. UA (mg/dl) was measured during early hospitalization. Patient survival status was followed up after discharge (median follow-up: 330 days). The independent association of UA level with all-cause mortality was analyzed using Cox regression analysis.

RESULTS

During follow-up 165 (29.5%) deaths were identified. Patients with UA levels above the median value (>or=7.7 mg/dl) exhibited higher mortality rates (21.1 vs. 37.9%; p<0.001). In multivariable analysis, after adjusting for recognized prognostic factors and potential confounders, UA>or=7.7 mg/dl and per change in 1 mg/dl of UA was associated with an increased risk of mortality (HR 1.45, CI 95%=1.03-2.44; p=0.03 and HR 1.08, CI 95%=1.01-1.15; p=0.03, respectively).

CONCLUSION

UA serum levels is an independent predictor of all-cause mortality in an unselected patients admitted with AHF.

Role of xanthine oxidoreductase in cardiac nitroso-redox imbalance

Emerging evidence supports the importance of nitroso-redox balance in the cardiovascular system. Xanthine oxidoreductase (XOR) is a major oxidative enzyme and increased XOR activity, leading to both increased production of reactive oxygen species and uric acid, is implicated in heart failure. Within the heart, XOR activity stimulates cardiomyocyte hypertrophy, apoptosis, and impairs matrix structure. The underpinnings of these derangements can be linked not solely to oxidative stress, but may also involve the process of nitroso-redox imbalance. In this regard, XOR interacts with nitric oxide signaling at numerous levels, including a direct protein-protein interaction with neuronal nitric oxide synthase (NOS1) in the sarcoplasmic reticulum. Deficiency or translocation of NOS1 away from this microdomain leads to increased activity of XOR, which in turn impairs excitation-contraction coupling and myofilament calcium sensitivity. There is a mounting abundance of preclinical data supporting beneficial effects of inhibiting XOR, but translation to the clinic continues to be incomplete. A growing understanding of XOR and its role in nitroso-redox imbalance has great potential to lead to improved pathophysiologic insights and possibly therapeutic advances.

Prevalence of Metabolic Syndrome in Patients With Clinically Advanced Peripheral Vascular Disease

The aim of this cross-sectional study was to determine the prevalence of metabolic syndrome (MetS) and its components among 100 patients with progressive peripheral arterial disease (PAD) referred for diagnostic angiography in preparation for a revascularization procedure. The prevalence of MetS was more than 95%. Diabetes mellitus was the most prevalent component followed by hypertension and low high-density lipoprotein. Almost half the patients aggregated in the highest metabolic score category. A direct relationship was identified between the number of MetS components and serum uric acid ( P = .001) and C-reactive protein ( P = .826), whereas an inverse relationship was seen between the clustering of components and androgen levels in men ( P < .001). For PAD, which could have a benign clinical course, early screening for MetS might identify those at greater risk of failing conservative therapy and progressing to a more aggressive atherosclerotic disease typically associated with high morbidity and mortality.

Hyperhomocysteinemia in patients with symptomatic chronic heart failure: Prevalence and prognostic importance—pilot study

BACKGROUND

Patients with chronic heart failure (CHF) may be particularly susceptible to unfavorable effects of hyperhomocysteinemia (HHcy). The aim of this study was to assess the prevalence of HHcy (plasma homocysteine [Hcy]>or=14 micromol/L) in an unselected cohort of CHF patients, its clinical determinants, and prognostic implications.

METHODS AND RESULTS

In 108 consecutive CHF patients (81 men, age: 66+/-11 years) with mean plasma Hcy level 12.5+/-5.5 micromol/L (range 2.3-28.3 micromol/L), 38 (35%) patients demonstrated HHcy. Among clinical and metabolic parameters, in multivariable regression models, advanced NYHA class (P<0.0001), plasma NT-proBNP (P<0.001), peak oxygen consumption (P<0.05), reduced glomerular filtration rate (P<0.0001) and elevated serum uric acid (P<0.05) predicted high plasma Hcy level. HHcy was related to increased mortality (HR=3.26, 95% CI: 1.78-5.98, P=0.0001), also when adjusted for conventional prognosticators in multivariable models (all P<0.01). In patients with HHcy, a 3-year survival was 37% (95% CI: 22-52%) as compared to 73% (95% CI: 63-83%) in those with normal Hcy levels (P<0.0001).

CONCLUSIONS

HHcy is common in CHF, is related to the disease severity, depicts generalized metabolic imbalance (evidenced by hyperuricaemia), and independently predicts poor long-term prognosis.

Serum uric acid is associated with microvascular function in hypertensive individuals

We investigated the relationship of serum uric acid (UA) with resting forearm blood flow (FBF), reactive hyperaemia (RH) and flow-mediated dilation (FMD) of the brachial artery in hypertensive adults (n=506, mean age 62 years, 59% women). UA was measured by a colorimetric method. FBF, RH and FMD were measured by brachial artery ultrasound. Regression analyses were used to assess whether UA was associated with FBF, RH and FMD before and after adjustment for age, sex, systolic BP, diabetes, total and high-density lipoprotein cholesterol, smoking, body mass index (BMI), C-reactive protein (CRP), serum creatinine, alcohol intake, statin and diuretic use and brachial artery diameter (BAD). UA was significantly associated with FBF (P<0.0001) and RH (P=0.0001) but not with FMD (P=0.43). After adjustment for the covariates listed above, higher UA level remained independently associated with a higher FBF (P=0.012) and lower RH (P=0.004). The independent predictors were as follows: (a) higher FBF: lower age, higher BMI, history of smoking, statin use, higher CRP, higher BAD and higher UA levels; (b) lower RH: higher BMI, diabetes and higher UA levels; (c) lower FMD: greater age, male sex, higher BMI, history of smoking, statin use and higher BAD. We conclude that in hypertensive individuals, higher UA levels are associated with higher resting FBF and lower RH, markers of microvascular function, but not with brachial artery FMD.

Elevated serum uric acid levels impair coronary microvascular function in patients with idiopathic dilated cardiomyopathy

In patients with idiopathic dilated cardiomyopathy (IDC), attenuated coronary flow reserve (CFR) and elevated serum uric acid levels have been reported. In this study, we investigated whether increased uric acid levels correlate with the degree of coronary microvascular dysfunction. Serum uric acid levels were measured in 29 patients with IDC (mean age: 57.0+/-10.8 years, 10 female), and each patient also underwent transthoracic echocardiographic examination including CFR measurement. The study population was divided into two groups according to the median CFR value (lower CFR group and higher CFR group). Uric acid levels were significantly higher in the lower CFR group than in the higher CFR group (7.59+/-2.56 vs 4.80+/-0.80 mg/dL, P=0.000). CFR correlated significantly and inversely to serum uric acid (r=-0.570, P=0.001). Logistic regression analysis revealed that uric acid level was the only independent predictor of CFR (B=-1080, P=0.015). We found a possibly clinically important negative association between serum uric acid levels and CFR in patients with IDC.

Hyperuricaemia predicts poor outcome in patients with mild to moderate chronic heart failure

BACKGROUND

In severe chronic heart failure (CHF) elevated serum levels of uric acid (UA) predict poor survival. This study investigates whether hyperuricaemia (defined as serum UA level > or = 6.5 mg/dL) extends its prognostic value on population with less advanced CHF.

METHODS

We studied 119 consecutive patients with stable, mild-moderate CHF (88 men, age: 64+/-11 years, NYHA class I/II/III: 9/65/45, LVEF: 32+/-8%).

RESULTS

Serum UA level (mean: 6.2+/-2.0 mg/dL, range: 2.0-16.2 mg/dL) increased in parallel to CHF severity expressed as NYHA class (4.9+/-1.1 vs. 5.7+/-1.5 vs. 7.2+/-2.4 mg/dL, NYHA I vs. II vs. III; NYHA I, II vs. III, p<0.01), inversely correlated with peak oxygen consumption (r=-0.39, p<0.01) and LVEF (r=-0.31, p<0.01), but not with renal function (expressed as creatinine clearance calculated from Cockcroft-Gault formula; r=-0.14, p>0.1), and predicted inflammatory status as evidenced by the correlation with C-reactive protein (r=0.31, p=0.003). Hyperuricaemia was detected in 48 (40%) patients. During follow-up (mean: 580+/-209 days, > 18 months in all survivors), 27 (23%) patients died. Hyperuricaemia was related to impaired survival in univariate (HR 2.8, 95%CI: 1.3-6.1, p=0.01) and multivariate analyses (adjusted for NYHA class and impaired renal function--the only mortality predictors in this population; p<0.05). The 18-month survival for CHF patients with hyperuricaemia was 71% (95% CI: 58-84%) vs. 89% (95% CI: 81-96%) in those with normal UA level (p=0.01).

CONCLUSION

In patients with mild-moderate CHF, hyperuricaemia predicts exercise intolerance and inflammatory activation and is strongly and independently related to poor prognosis. Whether elevated serum UA level may become a novel therapeutic target in CHF, deserves further studies.

Prevalence of hyperuricemia and its relationship with metabolic syndrome in Thai adults receiving annual health exams

BACKGROUND

Associations between hyperuricemia, metabolic syndrome, cardiovascular disease and diabetes have been reported. Limited information, however, is available concerning the prevalence and correlates of hyperuricemia among Thai men and women. We sought to estimate the prevalence of hyperuricemia among a population of patients receiving annual health exams and to evaluate its relationship with metabolic syndrome (MetS).

METHODS

We conducted a cross-sectional study of 1,381 patients (376 men and 1,005 women) who first participated in annual health examinations at the Preventive Medicine Clinic of the King Chulalongkorn Memorial Hospital in Bangkok, Thailand during the period July 1999 through February 2000. Hyperuricemia was defined as >7.0 mg/dL in men and >6.0 mg/dL in women. MetS was defined using the modified ATP III criteria.

RESULTS

The overall prevalence of the hyperuricemia was 10.6%. The condition was more common in men than in women (18.4 vs. 7.8%). Among women, serum uric acid was statistically significantly correlated with body mass index (BMI), systolic and diastolic blood pressure, high-density lipoprotein-cholesterol, triglyceride and fasting plasma glucose (all p <0.05). Men with serum uric acid concentrations >6.7 mg/dL (upper quartile) had a 3.91-fold increased in risk of MetS (95% CI:1.36-11.23), as compared with those who had concentrations <5.1 mg/dL (lowest quartile). Among women, the risk of MetS increased at least 2-fold for concentration of serum uric acid concentrations >4.0 mg/dL (p for trend <0.001).

CONCLUSIONS

Hyperuricemia is prevalent among Thai men and women receiving routine health exams. Additionally, serum uric acid is positively associated with MetS.

Urate oxidation during percutaneous transluminal coronary angioplasty and thrombolysis in patients with coronary artery disease

Thrombolysis and percutaneous transluminal coronary angioplasty (PTCA) are kinds of procedures that can be used to restore the blood flow of previously ischemic myocardium that can be the result of excessive production of reactive oxygen and nitrogen species, such as superoxide and hydroxyl radical, hypochlorous acid and peroxynitrite. Reaction of urate with some of these potent oxidants results in allantoin production. In this study, we measured the serum allantoin levels, an oxidation product of urate, and "in vivo" marker of free radical generation in reperfusion of ischemic myocardium. After an overnight fasting state, blood samples were collected from 35 patients with coronary occlusive diseases (7 women and 28 men) and 31 healthy subjects (8 women and 23 men). Serum allantoin and urate levels were measured by a GC-MS method. Serum allantoin levels of patients on PTCA therapy (mean+/-SD, 27.4 +/- 15.2 micromol/l) and thrombolytic therapy (24.6 +/- 8.6 micromol/l) were significantly higher than those of the patients without therapy (15.8 +/- 6.2 micromol/l, p < 0.05 with PTCA and p < 0.006 with thrombolysis) and healthy controls (12.6 +/- 6.3 micromol/l, p < 0.002 with PTCA and p < 0.0001 with thrombolysis). Although serum urate levels in PTCA (380.1 +/- 72.6 micromol/l) and thrombolysis (359.5 +/- 60.0 micromol/l) were higher than those in the non-therapy patients (336.6 +/- 53.8 micromol/l) and controls (318.3 +/- 81.0 micromol/l), there were no significant differences among groups (p > 0.05). The results of the study are consistent with others which have demonstrated, higher urate levels are associated with coronary occlusive diseases. Our data support the hypothesis that generation of ROS occurs during myocardial reperfusion. Increased allantoin levels may be used as an index of increased oxidative stress during reperfusion.

Serum uric acid and cardiovascular disease: recent developments, and where do they leave us?

The relationship between serum uric acid (SUA) and cardiovascular disease has been controversial. Here we review recent literature assessing whether hyperuricemia is an independent risk factor for adverse cardiovascular outcomes. Studies from the past 6 years evaluating the association of SUA with cardiovascular disease were identified through MEDLINE, EMBASE, and Cochrane library searches, bibliography cross-referencing, and review articles. Twenty-one cohort studies in healthy and high-risk patients with cardiovascular disease were identified and reviewed. In studies of high-risk patients, in which more overall events were recorded, 10 of 11 studies were supportive of an independent association. In 10 studies of healthy patients, 6 suggested an independent association of SUA with adverse cardiovascular outcomes. Increasing SUA is likely an independent risk factor for cardiovascular disease in high-risk individuals. However, the magnitude of excess risk attributable to high SUA is likely to be small in healthy individuals. Trials of SUA-lowering therapy in hyperuricemic patients evaluating the effect on cardiovascular outcomes are justified in high-risk patients.

Hyperuricemia as a predictor of hypertension in a screened cohort in Okinawa, Japan

Several epidemiological studies have shown a positive association between serum uric acid levels and the risk of hypertension. However, subjects in these studies were mostly men, or were incompletely examined for lifestyle-related variables. We prospectively examined the relation between hyperuricemia and the risk of developing hypertension with consideration for alcohol consumption and smoking habits in a large screened cohort of men and women. A total of 4,489 individuals (2,927 men and 1,562 women) who did not have hypertension and were not currently using antihypertensive medication were examined at the Okinawa General Health Maintenance Association in 1977. Subjects were re-examined in 2000. Hyperuricemia was defined as a serum uric acid level >or=7.0 mg/dl in men and >or=6.0 mg/dl in women. Hypertension was defined as systolic blood pressure (SBP) >or=140 mmHg, and/or diastolic blood pressure (DBP) >or=90 mmHg. A total of 289 subjects (201 men and 88 women) were hypertensive (SBP >or=140 mmHg, and/or DBP >or=90 mmHg) in 2000. Multivariate analysis was performed for development of hypertension in hyperuricemic subjects, adjusted for age, family history of hypertension, alcohol consumption, cigarette smoking, obesity, hypercholesterolemia, hypertriglyceridemia, low high-density lipoprotein cholesterol, and diabetes mellitus. The adjusted odds ratio (95% confidence interval) in men was 1.48 (1.08-2.02) and in women was 1.90 (1.03-3.51) (p <0.05, respectively). The results showed hyperuricemia to be a new predictor of hypertension development in both men and women.

Uric acid in chronic heart failure

The pathophysiologic understanding of chronic heart failure (CHF) has shifted from a mere hemodynamic disorder to a much more complex approach including changes and imbalances in neurohormonal, immune, and metabolic functions. Among metabolic abnormalities, hyperuricemia is a constant finding in CHF. The xanthine oxidase metabolic pathway increasingly is appreciated as an important contributor to both symptoms of CHF as well as progression of the disease. Recent data suggest hyperuricemia to be an independent marker of impaired prognosis in CHF. In this article, the significance of the xanthine oxidase metabolic pathway in CHF is discussed. Data on xanthine oxidase inhibition are reviewed, which suggest a beneficial effect of therapeutically targeting this enzymatic pathway.

Pulsed electric fields-processed orange juice consumption increases plasma vitamin C and decreases F2-isoprostanes in healthy humans

Orange juice, a rich source of vitamin C, accounts for 60% of all fruit juices and juice-based drinks consumed in western Europe. Orange juice preservation is currently accomplished by traditional pasteurization. Pulsed electric fields (PEF) have been studied as a nonthermal food preservation method. Food technology needs in the area of processing are driven by nutrition. Therefore, the objectives of this study were to assess the bioavailability of vitamin C from pulsed electric fields-treated orange juice in comparison with freshly squeezed orange juice and its impact on 8-epiPGF(2alpha) concentrations (biomarker of lipid peroxidation) in a healthy human population. Six subjects consumed 500 mL/day of pulsed electric fields-treated orange juice and six subjects consumed 500 mL/day of freshly squeezed orange juice for 14 days, corresponding to an intake of about 185 mg/day of ascorbic acid. On the first day of the study, subjects drank the juice in one dose, and on days 2-14 they consumed 250 mL in the morning and 250 mL in the afternoon. Blood was collected every hour for 6 hours on the first day and again on days 7 and 14. In the dose-response study, the maximum increase in plasma vitamin C occurred 4 hours postdose. Vitamin C remained significantly higher on days 7 and 14 in both orange juice groups. Plasma 8-epiPGF(2alpha) concentrations was lower at the end of the study (P < 0.001) in both groups. Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated. Pulsed electric fields-preservation of orange juice retains the vitamin C bioavailability and antioxidant properties of fresh juice with a longer shelf-life.

Effect of statins versus untreated dyslipidemia on serum uric acid levels in patients with coronary heart disease: a subgroup analysis of the GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study

BACKGROUND

Little is known about the effect of dyslipidemia on serum uric acid (SUA) levels, and less is known about the effect of statin treatment on them. The GREek Atorvastatin and Coronary-heart-disease Evaluation study suggested that a mean atorvastatin dose of 24 mg/d achieves the National Cholesterol Educational Program treatment goals and significantly reduces morbidity and mortality in patients with coronary heart disease (CHD) in comparison to the usual care. Here, we report the time course of SUA levels in usual-care patients undertreated for their dyslipidemia (12% were administered statins) in comparison to structured-care patients treated with atorvastatin in the vast majority (98%).

METHODS

Mean on-study SUA levels (up to 48 months) were compared with those at baseline by using analyses of variance to assess differences over time within and between treatment groups. Cox multivariate analysis was used to investigate whether changes in SUA levels during the study were clinically relevant.

RESULTS

All patients had normal renal function at baseline; serum creatinine (SCr) levels less than 1.3 mg/dL (<115 micromol/L) and moderately elevated SUA levels (mean, 7.1 +/- 0.9 [SD] mg/dL [425 +/- 52 micromol/L]; upper normal limit, 7.0 mg/dL [415 micromol/L]). Usual-care patients (n = 800) showed an increase in SUA levels by 3.3% ( P < 0.0001). Structured-care patients (n = 800) had an 8.2% reduction in SUA levels ( P < 0.0001). In all patients not administered diuretics (n = 1,407), SUA level changes showed a positive correlation with changes in SCr levels ( r = 0.82; P < 0.0001) and an inverse correlation with estimated glomerular filtration rate ( r = -0.77; P < 0.0001). After adjustment for 19 predictors of all CHD-related events, Cox multivariate analysis involving backward stepwise logistic regression showed a hazard ratio (HR) of 0.89 (95% confidence interval [CI], 0.78 to 0.96; P = 0.03) with every 0.5-mg (30-micromol/L) reduction in SUA level, an HR of 0.76 (95% CI, 0.62 to 0.89; P = 0.001) with every 1-mg (60-micromol/L) reduction, an HR of 1.14 (95% CI, 1.03 to 1.27; P = 0.02) with every 0.5-mg increase, and an HR of 1.29 (95% CI, 1.17 to 1.43; P = 0.001) with every 1-mg increase in SUA levels.

CONCLUSION

Data suggest that SUA level is an independent predictor of CHD recurrent events. Atorvastatin treatment significantly reduces SUA levels in patients with CHD, thus offsetting an additional factor associated with CHD risk.

Role of xanthine oxidase in conduit artery endothelial dysfunction in cigarette smokers

Xanthine oxidase contributes to oxidant stress and has been proposed as a risk factor for endothelial dysfunction. We studied the role of xanthine oxidase in conduit artery endothelial dysfunction in 12 smokers and 12 controls. Conduit artery vasodilation was impaired in smokers (4.3%) compared with controls (7.9%) (p = 0.006) and improved with xanthine oxidase inhibition in smokers (9.2%, p <0.001).

Effect of orange juice intake on vitamin C concentrations and biomarkers of antioxidant status in humans

BACKGROUND

Consumption of fruit and vegetables is associated with improved health and a decreased prevalence of chronic degenerative processes.

OBJECTIVES

The objectives were to assess the bioavailability of vitamin C from orange juice and its influence on plasma vitamin C and 8-epi-prostaglandin F(2 alpha) (8-epi-PGF(2 alpha)) concentrations in a healthy human population.

DESIGN

Six men and 6 women consumed 500 mL commercial fresh-squeezed orange juice/d for 14 d, corresponding to an intake of 250 mg ascorbic acid/d. On the first day of the study, the subjects drank the juice in one dose (dose-response study), and on days 2-14 they consumed 250 mL in the morning and 250 mL in the afternoon. Blood was collected every hour for 6 h on the first day and again on days 7 and 14.

RESULTS

Baseline plasma vitamin C concentrations were significantly higher (P = 0.03) among the women than among the men (56.4 +/- 4.4 compared with 44.3 +/- 3.5 micromol/L). In the dose-response study, the maximum increase in plasma vitamin C occurred 3 h postdose in both the men and the women. Vitamin C concentrations remained significantly higher on days 7 and 14 than at baseline. Baseline concentrations of 8-epi-PGF(2 alpha) were significantly higher (P = 0.03) among the men than among the women (249.6 +/- 25.4 compared with 177.7 +/- 6.2 pg/mL) but decreased significantly (P = 0.04) by day 14 of the intervention. A significant inverse correlation was observed between vitamin C and 8-epi-PGF(2 alpha) (r = -0.791, P = 0.0022). Among smokers, baseline vitamin C was lower and 8-epi-PGF(2 alpha) higher than among nonsmokers.

CONCLUSIONS

Drinking orange juice (500 mL/d) increases plasma concentrations of vitamin C and reduces concentrations of 8-epi-PGF(2 alpha) in humans. These effects were significantly more pronounced in smokers.

High-pressurized orange juice consumption affects plasma vitamin C, antioxidative status and inflammatory markers in healthy humans

We examined the bioavailability of vitamin C in orange juice processed using high pressure (HP) and its effects on plasma levels of vitamin C, uric acid (UA), F2-isoprostanes (8-epiPGF(2alpha)), C-reactive protein (CRP) and prostaglandin E(2) (PGE(2)) in a healthy human population. Subjects (6 men, 6 women) enrolled in the study consumed 500 mL/d of HP orange juice for 14 d, corresponding to an intake of 250 mg of vitamin C. On d 1 of the study, subjects drank the juice in one dose; on d 2 until the end of the study, d 14, they drank 250 mL in the morning and 250 mL in the afternoon. Blood was collected every h for 6 h, on d 1, and then on d 7 and 14 of the study. Baseline plasma vitamin C concentration was higher (P = 0.014) in women (55.8 +/- 3.8 micro mol/L) than in men (42.8 +/- 2.1 micro mol/L). The maximum plasma vitamin C increase occurred 3 h after drinking the juice, and it remained elevated on d 7 and 14. Plasma 8-epiPGF(2alpha) concentration did not differ between men and women at baseline. However, it was lower at the end of the study in both men (P = 0.044) and women (P = 0.034). Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated (r = -0.615, P = 0.001). Plasma CRP concentrations tended to be lower on d 14 than at baseline in men (P = 0.317) and women (P = 0.235). Plasma PGE(2) was lower at the end of the study in both men and women (P <or= 0.037). Drinking orange juice increases plasma vitamin C, and decreases 8-epiPGF(2alpha) and PGE(2) levels in humans, which may help reduce the risk of chronic diseases.

Serum uric acid in hypertensive patients with and without peripheral arterial disease

BACKGROUND

Uric acid is frequently elevated in hypertension. In addition to renal and metabolic disturbances, lower limb ischemia might contribute to hyperuricemia among hypertensives complicated by peripheral arterial disease (PAD).

OBJECTIVE

To test the hypothesis that uric acid status is related to lower limb function in hypertensives with PAD.

METHODS

Serum and 24-h urine uric acid levels and other risk factors were examined in 145 hypertensives free of PAD and 166 hypertensives with PAD. Ankle/brachial index (ABI) and absolute claudication distance (in PAD) on a treadmill test (ACD) were assessed.

RESULTS

In multiple regression analysis for serum uric acid in the total group, PAD emerged as an independent determinant (P=0.03) next to age (P=0.005), triglycerides (P=0.04), and insulin (P=0.02). Serum uric acid concentrations were higher in hypertensives with PAD (404+/-101 vs. 347+/-80 micromol/l, P<0.001) independent of components of the metabolic syndrome (body mass index, triglycerides, insulin) and of age, gender, diabetes mellitus, pulse pressure, cholesterol, C-reactive protein, and treatment. After adjustment for kidney function by uric acid/creatinine ratio, values remained higher in hypertensives with PAD (P=0.01). Uric acid excretion was higher in the PAD group (P<0.001), whereas uric acid clearance was comparable between both groups. In multiple regression analysis for ACD (357+/-183 m) in the PAD group, serum uric acid (P=0.02), C-reactive protein (P<0.0001), age (P=0.02), and smoking (P=0.004) were independently associated. ABI (0.62+/-0.17) was not related to uric acid in PAD patients.

CONCLUSION

Hyperuricemia is more pronounced in hypertensives complicated by PAD and is associated with worse functional status of the peripheral circulation.

Uric acid and survival in chronic heart failure: validation and application in metabolic, functional, and hemodynamic staging

BACKGROUND

Serum uric acid (UA) could be a valid prognostic marker and useful for metabolic, hemodynamic, and functional (MFH) staging in chronic heart failure (CHF).

METHODS AND RESULTS

For the derivation study, 112 patients with CHF (age 59+/-12 years, peak oxygen consumption [Vo2] 17+/-7 mL/kg per minute) were recruited. In separate studies, we validated the prognostic value of UA (n=182) and investigated the relationship between MFH score and the decision to list patients for heart transplantation (n=120). In the derivation study, the best mortality predicting UA cutoff (at 12 months) was 565 micromol/L (9.50 mg/dL) (independently of age, peak Vo2, left ventricular ejection fraction, diuretic dose, sodium, creatinine, and urea; P<0.0001). In the validation study, UA >or=565 micromol/L predicted mortality (hazard ratio, 7.14; P<0.0001). In 16 patients (from both studies) with UA >or=565 micromol/L, left ventricular ejection fraction <or=25% and peak Vo2 <or=14 mL/kg per min (MFH score 3), 12-month survival was lowest (31%) compared with patients with 2 (64%), 1 (77%), or no (98%, P<0.0001) risk factor. In an independent study, 51% of patients with MFH score 2 and 81% of patients with MFH score 3 were listed for transplantation. The positive predictive value of not being listed for heart transplantation with an MFH score of 0 or 1 was 100%.

CONCLUSIONS

High serum UA levels are a strong, independent marker of impaired prognosis in patients with moderate to severe CHF. The relationship between serum UA and survival in CHF is graded. MFH staging of patients with CHF is feasible.

Elevated serum leptin concentrations in women with hyperuricemia

The serum uric acid level has been said to be an independent predictor of cardiovascular disease death, mainly for women, and to be linked with the metabolic Syndrome X of insulin resistance, obesity, hypertension, and dyslipidemia. Recently, it has been suggested that the elevation of serum leptin, the ob gene product, may have a role in metabolic Syndrome X. Therefore, we studied the relationship of uric acid to leptin in 822 Japanese women in a cross-sectional manner. To estimate the effect of uric acid on the variables of metabolic Syndrome X, we calculated mean values of various components of the syndrome according to tertiles of uric acid (UA < 4.0 mg/dl, 4.0 < or = UA < 5.5, 5.5 < or = UA). Age, systolic and diastolic blood pressure (BP), body mass index (BMI), percent body fat mass (BFM), serum total cholesterol, triglyceride, atherogenic index, leptin, fasting immunoreactive insulin and homeostasis model assessment-ratio (HOMA-R: calculated insulin resistance) were significantly different across the uric acid tertiles with higher levels in the highest tertile in comparison to the first (ANOVA, p < 0.001, 0.001, 0.002, 0.001, 0.001, 0.025, 0.001, 0.001, 0.001, 0.001, 0.001, respectively), while high density lipoprotein cholesterol showed lower levels (p < 0.001). Serum leptin concentrations were also elevated in hyperuricemic women after adjusting for BMI or BFM (both p < 0.001), and were weakly correlated with serum uric acid concentrations (r = 0.22, p < 0.0001). BMI, HOMA-R, serum triglyceride, diastolic BP and age-adjusted serum leptin concentrations were calculated for each tertile of serum uric acid. Compared with the lowest tertile of uric acid level, BMI, HOMA-R, serum triglyceride, diastolic BP and age-adjusted leptin concentrations were higher in the highest tertile. In the stepwise regression analysis, serum leptin was the significant independent variable for uric acid values. These results indicate an independent relationship between leptin and uric acid, further supporting the involvement of leptin in metabolic Syndrome X.

Xanthine oxidase inhibition reverses endothelial dysfunction in heavy smokers

BACKGROUND

Cigarette smoking causes endothelial dysfunction, possibly through increased oxidant stress. The enzyme xanthine oxidase produces oxidative free radicals. We tested the hypothesis that xanthine oxidase contributes to endothelial dysfunction in cigarette smokers by administering the inhibitor allopurinol.

METHODS AND RESULTS

Fourteen cigarette smokers (31+/-4 pack years) and 14 age- and sex-matched healthy non-smoking control subjects participated in a single-blinded, randomized, 2-phase crossover study. All subjects had no other risk factors for atherosclerosis. Inhibition of xanthine oxidase was achieved by a single oral dose of 600 mg of allopurinol on the day of the study. Stimulated nitric oxide endothelial responses were assessed by forearm blood flow responses to intraarterial administration of acetylcholine and bradykinin 4 to 7 hours later; basal nitric oxide was assessed using the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA); and nitroprusside was used to assess sensitivity to nitric oxide. Dilatation produced by acetylcholine was significantly less in smokers (254+/-57%) than healthy controls (390+/-55%) (P=0.009). Allopurinol reversed endothelial dysfunction in smokers (acetylcholine, 463+/-78%, P=0.001) without affecting responses in non-smokers (401+/-80%). Bradykinin responses were also impaired in smokers (P=0.003), and improved with allopurinol, though not significantly (P=0.06). Responses to nitroprusside and L-NMMA were not significantly different between smokers and controls and were not altered by allopurinol.

CONCLUSIONS

Smoking-induced endothelial dysfunction of resistance vessels is rapidly reversed with oral allopurinol. These data suggest that xanthine oxidase contributes importantly to endothelial dysfunction caused by cigarette smoking.