Uric acid in heart failure: a biomarker or therapeutic target?

Biosensors for Parkinson's Disease: Where Are We Now, and Where Do We Need to Go?

Parkinson's Disease is the second most common neurological disease in the United States, yet there is no cure, no pinpointed cause, and no definitive diagnostic procedure. Parkinson's is typically diagnosed when patients present with motor symptoms such as slowness of movement and tremors. However, none of these are specific to Parkinson's, and a confident diagnosis of Parkinson's is typically only achieved when 60-80% of dopaminergic neurons are no longer functioning, at which point much of the damage to the brain is irreversible. This Perspective details ongoing efforts and accomplishments in biosensor research with the goal of overcoming these issues for Parkinson's diagnosis and care, with a focus on the potential impact of early diagnosis and associated opportunities to pinpoint a cause and a cure. We critically analyze the strengths and shortcomings of current technologies and discuss the ideal characteristics of a diagnostic technology toolbox to guide future research decisions in this space. Finally, we assess what role biosensors can play in facilitating precision medicine for Parkinson's patients.

Induction of P-glycoprotein expression by dandelion in tumor and heart tissues: Impact on the anti-tumor activity and cardiotoxicity of doxorubicin

BACKGROUND

Previously, we have investigated the anti-tumor activity and mechanism through which dandelion acts against triple-negative breast cancer (TNBC). However, traditional Chinese medicine is mostly accepted as an adjunct therapy during chemotherapy in clinical practice. So far, little is known about the effects of dandelion in conjunction with chemotherapeutic drugs.

PURPOSE

To investigate the effects of dandelion on the anti-tumor activity and cardiotoxicity of doxorubicin (DOX), and to further explore the molecular mechanisms through which these effects occur.

STUDY DESIGN

At the beginning of this study, dandelion was observed to alleviate DOX-induced cardiotoxicity and reduce the anti-tumor activity of DOX. Subsequently, we investigated whether the resistance to DOX mediated by P-glycoprotein was involved in the above effects.

METHODS

The cardioprotective effect of dandelion was investigated on DOX-treated mice by histological analysis, myocardial enzyme assays, and an untargeted metabolomics study based on LC-Q-TOF/MS. TNBC cell lines and 4T1 tumor-bearing mice were employed to investigate the combined anti-tumor activity. Laser scanning confocal microscope and a flow cytometry analysis were employed to measure the intracellular accumulation of DOX. A specific, sensitive, and rapid LC-MS/MS method was developed to detect the efflux of DOX from cells. Expression of P-glycoprotein in mouse tumor and heart tissues was detected via Western blotting analysis.

RESULTS

Dandelion was found to significantly alleviate DOX-induced cardiotoxicity, as was evidenced by improved cardiomyocyte morphology, decreased LDH and CK-MB release, and adjusted metabolic biomarker levels. However, in vitro and in vivo studies showed that dandelion could reduce the anti-tumor activity of DOX. This counteraction was achieved by activating of the drug efflux transporter P-glycoprotein, thereby promoting the efflux of DOX from cells and reducing the intracellular accumulation of DOX. Moreover, the activation of P-glycoprotein by dandelion in mouse heart tissue was also observed, thus suggesting that the decrease of cardiac DOX accumulation plays an important role in the cardioprotective effect of dandelion.

CONCLUSION

Dandelion can activate the P-glycoprotein in heart and tumor tissues, which ameliorates DOX-induced cardiotoxicity but attenuates DOX cytotoxicity toward TNBC. Our findings have important implications for the correct clinical use of dandelion.

Occurrence of metabolic syndrome components in northerners

The metabolic syndrome is currently becoming more common. It is a significant public health concern as it is epidemic affecting populations in many regions of the world. In Magadan region no research has been carried out to study the frequency of components of the metabolic syndrome among northerners. This survey was performed to assess the occurrence of the main and additional components of the metabolic syndrome among 17 to 74 year old residents of the Northern region. Two hundred and forty north born Caucasians participated in the study: male subjects at their young age, working age, and retirement age, all belonging to the territory of Magadan region. We used photometric, immunochemiluminescent research methods, as well as standard methods for assessing body mass index and cardiovascular system. The metabolic syndrome factors were determined in accordance with the criteria of the National Cholesterol Education Program (NCEP), the Adult Treatment Program III (ATP III), the International Diabetes Federation (IDF), and the Consensus of International Experts in Cardiology and Endocrinology. We analyzed five main components of the metabolic syndrome (overweight, carbohydrate metabolic impairments hypertension, hypertriglyceridemia, hypoalphacholesterolemia) and three additional components (presence of insulin resistance, purine metabolism disorder, deficient and insufficient concentrations of vitamin D). Combinations of the components were also studied through the examined age groups. According to the ATP III, NCEP and IDF criteria, the metabolic syndrome was more common in elderly subjects (47%) than in working age (21%) or young examinees (3%). Older males tended to exhibit higher frequency of both the main and additional factors of metabolic syndrome. The total index of the occurrence of metabolic syndrome factors in the group of young men was 101%; in the group of men of working age - 180%, and in men of retirement age - 274%. The results on occurrence of the metabolic syndrome components observed in the surveyed groups of northerners can make an information data base, which we assume can be applied when planning and carrying out scientifically grounded preventive measures, which will improve subjective quality of life and its expectancy under the North conditions.

Risk factors of short-term, intermediate-term, and long-term cardiac events in patients hospitalized for HFmrEF

AIMS

Clinical data on the prognostic determinants over varying periods within the same cohort of heart failure with mid-range or mildly reduced ejection fraction (HFmrEF) remain scarce. This study aimed to identify the short-term, intermediate-term, and long-term risk factors of adverse cardiovascular (CV) outcomes in patients hospitalized for HFmrEF.

METHODS AND RESULTS

This retrospective study included 1691 consecutive HFmrEF patients admitted to our hospital between January 2015 and August 2020. Baseline data including clinical characteristics, laboratory and cardiac imaging examinations were obtained. Patients completed at least 1 year clinical follow-up after discharge by telephone interview, clinical visit, or community visit. The primary endpoint was defined as a composite of CV death or rehospitalization for heart failure (CV events) at 3, 12, and 33 months after the diagnosis of HFmrEF. Mean age of the whole cohort was 69 (61-77) years and 64.8% were male. The median clinical follow-up was 33 (20-50) months. CV events were 17.5%, 28.2%, and 57.8% at 3, 12, and 33 months after discharge, respectively. Independent risk factors for CV events were uric acid >382 μmol/L, creatinine >100 μmol/L, N-terminal pro-B type natriuretic peptide (NT-proBNP) > 3368 pg/mL and haemoglobin <120 g/L for men and <110 g/L for women at 3 and 12 months. Pulmonary artery systolic pressure >35 mmHg and the ratio of early transmitral flow velocity to early mitral annular velocity >18 served as independent risk factors for CV events at 12 months. At 33 months, uric acid > 382 μmol/L, NT-proBNP >3368 pg/mL, and pulmonary artery systolic pressure >35 mmHg were the independent risk factors of CV events.

CONCLUSIONS

Higher uric acid, creatinine, NT-proBNP, and lower haemoglobin levels at baseline are valuable serum biomarkers for risk stratification of short-term and long-term CV outcomes of HFmrEF patients. Future studies are needed to verify if intensive heart failure therapy for identified high-risk HFmrEF patients based on these four serum biomarkers could improve their short-term and long-term CV outcomes or not.

Prognostic impacts of serum uric acid levels in patients with chronic heart failure: insights from the CHART-2 study

AIMS

Prognostic impacts of serum uric acid (UA) levels in patients with chronic heart failure (CHF) remain inconclusive, especially for the whole range of serum UA levels.

METHODS AND RESULTS

In the Chronic Heart Failure Registry and Analysis in the Tohoku District-2 (CHART-2) study, we enrolled 4652 consecutive patients with CHF and classified them into four groups based on baseline serum UA levels by the Classification and Regression Tree: G1 (<3.8 mg/dL, N = 313), G2 (3.8-7.1 mg/dL, N = 3070), G3 (7.2-9.2 mg/dL, N = 1018), and G4 (>9.2 mg/dL, N = 251). Mean age was 71 ± 12, 69 ± 12, 68 ± 13, and 69 ± 15 years in G1, G2, G3, and G4, respectively (P < 0.001). During the median follow-up of 6.3 years, in G1, G2, G3, and G4, 111 (35%), 905 (29%), 370 (36%), and 139 (55%) patients died and 79 (25%), 729 (24%), 300 (29%), and 115 (46%) experienced heart failure hospitalization, respectively (both P < 0.001). G1 was characterized by a significantly high prevalence of women as compared with G2, G3, and G4 (59%, 32%, 24%, and 23%, respectively). Serum creatinine levels (0.8 ± 0.4, 0.9 ± 0.4, 1.2 ± 0.6, and 1.4 ± 0.8 mg/dL, respectively), prevalence of atrial fibrillation (34%, 39%, 45%, and 50%, respectively), and diuretics use (36%, 45%, 67%, and 89%, respectively) increased from G1, G2, G3 to G4 (all P < 0.001), while left ventricular ejection fraction decreased from G1, G2, G3 to G4 (59 ± 15, 58 ± 15, 54 ± 15, and 52 ± 17%, respectively, P < 0.001). Multivariable Cox proportional hazards models showed that, as compared with G2, both G1 and G4 had increased incidence of all-cause death [adjusted hazard ratio (aHR) 1.34, 95% confidence interval (CI) 1.08-1.67, P = 0.009; aHR 1.28, 95% CI 1.02-1.61, P = 0.037, respectively] and heart failure admission (aHR 1.39, 95% CI 1.09-1.78, P = 0.008 and aHR 1.35, 95% CI, 1.06-1.71, P = 0.014, respectively). This U-shaped relationship was evident in the elderly patients. Furthermore, abnormal transitions to either higher or lower levels of serum UA from G2 were associated with increased mortality (aHR 1.29, 95% CI 1.06-1.57, P = 0.012; aHR 1.57, 95% CI 1.12-2.20, P = 0.009).

CONCLUSIONS

These results demonstrate that serum UA levels have the U-shaped prognostic effects and abnormal transitions to either higher or lower levels are associated with poor prognosis in the elderly patients with CHF.

Comparison of Characteristics and Outcomes of Patients With Heart Failure With Preserved Ejection Fraction With Versus Without Hyperuricemia or Gout

Hyperuricemia and gout are common in patients with heart failure (HF) and are associated with poor outcomes. Data describing hyperuricemia and gout in patients with HF with preserved ejection fraction (HFpEF) are limited. We used data from the Duke University Health System to describe characteristics of patients with HFpEF and hyperuricemia (serum uric acid >6 mg/dl) or gout (gout diagnosis or gout medication within the previous year) and to explore associations with 5-year outcomes (death and hospitalization). We identified 7,004 patients in the Duke University Health System with a known diagnosis of HFpEF who underwent transthoracic echocardiography between January 1, 2005 and December 31, 2017. A total of 1,136 (16.2%) patients with HFpEF also had hyperuricemia or gout. Patients with HFpEF and hyperuricemia or gout had a greater co-morbidity burden, more echocardiographic findings of cardiac remodeling, and higher unadjusted rates of all-cause death, all-cause hospitalization, and HF hospitalization compared with those with HFpEF without hyperuricemia or gout. After multivariable adjustment, patients with HFpEF and hyperuricemia or gout had a significantly higher rates of first all-cause hospitalization (adjusted hazard ratio 1.10 [95% confidence interval 1.02 to 1.19]; p = 0.020) and recurrent all-cause hospitalization (associated rate ratio 1.13 [95% confidence interval 1.01 to 1.25]; p = 0.026). After adjustment, no significant differences in death or HF hospitalization were observed. In conclusion, patients with HFpEF and hyperuricemia or gout were found to have a higher burden of co-morbidities and a higher rate of all-cause hospitalization, even after multivariable adjustment, compared to patients with HFpEF without hyperuricemia or gout.

Salivary lactate and 8-isoprostaglandin F2α as potential non-invasive biomarkers for monitoring heart failure: a pilot study

Heart failure (HF) is a cardiovascular disease affecting about 26 million people worldwide costing about $100 billons per year. HF activates several compensatory mechanisms and neurohormonal systems, so we hypothesized that the concomitant monitoring of a panel of potential biomarkers related to such conditions might help predicting HF evolution. Saliva analysis by point-of-care devices is expected to become an innovative and powerful monitoring approach since the chemical composition of saliva mirrors that of blood. The aims of this study were (i) to develop an innovative procedure combining MEPS with UHPLC-MS/MS for the simultaneous determination of 8-isoprostaglandin F2α and cortisol in saliva and (ii) to monitor lactate, uric acid, TNF-α, cortisol, α-amylase and 8-isoprostaglandin F2α concentrations in stimulated saliva samples collected from 44 HF patients during their hospitalisation due to acute HF. Limit of detection of 10 pg/mL, satisfactory recovery (95-110%), and good intra- and inter-day precisions (RSD ≤ 10%) were obtained for 8-isoprostaglandin F2α and cortisol. Salivary lactate and 8-isoprostaglandin F2α were strongly correlated with NT-proBNP. Most patients (about 70%) showed a significant decrease (a factor of 3 at least) of both lactate and 8-isoprostaglandin F2α levels at discharge, suggesting a relationship between salivary levels and improved clinical conditions during hospitalization.

Uric acid: from a biological advantage to a potential danger. A focus on cardiovascular effects

Non-communicable diseases represent nowadays the most common cause of death worldwide, having largely overcome infectious diseases. Among them, cardiovascular diseases constitute the majority. Given these premise, great efforts have been made by scientific societies to emphasize the fundamental role of cardiovascular prevention and risk factors control. In addition to classical cardiovascular risk factors such as smoking, arterial hypertension, hypercholesterolemia and male gender, new risk factors are emerging from international literature. Among them, uric acid is the protagonist. Several evidences show a direct role of hyperuricemia in the determinism of metabolic and vascular disorders. From the other hand, some researchers have demonstrated that uric acid is only a marker of cardiovascular damage and not a risk factor for its development. Aim of this review is to evaluate the scientific evidences on the role of uric acid in cardiovascular diseases in order to shed light on this confusing topic.

Prognostic value of serum uric acid in patients with acute heart failure: A meta-analysis

BACKGROUND

Conflicting results have been reported on the prognostic significance of serum uric acid (SUA) in patients with acute heart failure (AHF). This meta-analysis aimed to determine the prognostic significance of SUA level in patients with AHF.

METHODS

We made a comprehensive literature search in Pubmed and Embase databases from inception to April 6, 2018. All available observational studies or post hoc analysis of randomized controlled trial that evaluated the prognostic value of SUA level in patients with AHF were eligible. Outcome of interests were all-cause mortality and the combined endpoint of death or readmission. Prognostic values of SUA level were summarized as higher vs lower SUA category or per 1 mg/ml SUA rise.

RESULTS

Ten studies involving 12,854 AHF patients were identified and analyzed. AHF patients with the highest SUA level had an increased risk of all-cause mortality (risk ratio [RR] 1.43; 95% confidence intervals [CI] 1.31-1.56) and combined endpoint of death or readmission (RR 1.68; 95% CI 1.33-2.13) after adjusting potential variables. In addition, per 1 mg/ml SUA rise significantly increased by 11% and 12% higher risk all-cause mortality and combined endpoint of death or readmission, respectively. A leave out 1 study sensitivity analysis confirmed the reliability of the pooling effect sizes.

CONCLUSION

This meta-analysis indicates that elevated SUA level independently predicts all-cause mortality and the combined endpoint of death or readmission in AHF patients. Measurement of SUA level may improve risk stratification of adverse outcomes in these patients.

Gender-Related Association of Serum Uric Acid Levels with Premature Ventricular Contraction

In this study, we aim to investigate the association of serum uric acid (SUA) with the prevalence of premature ventricular contraction (PVC). The relationship between SUA and the prevalence of PVC in 98,965 subjects (79,034 male subjects, mean age: 51.9 ± 12.6 years old) in the Kailuan cohort study (n = 101,510, age range: 18-98 years) from June 2006 to October 2007 was investigated. These subjects were divided into five groups on the basis of their SUA levels. A multivariate logistic regression model was constructed to evaluate the association between SUA and the prevalence of PVC. The prevalence of PVC was 1.1% in all subjects, 1.1% in male subjects, and 1.0% in female subjects. Compared with the first quintile of SUA, the odds ratio (OR) and 95% confidence interval (95% CI) of other quintiles were 1.33 (1.05-1.69), 1.14 (0.90-1.46), 1.37 (1.08-1.74), and 1.63 (1.30-2.06) in male subjects; 1.12 (0.68-1.87), 1.27 (0.77-2.09), 1.45 (0.90-2.36), and 1.33 (0.81-2.18) in female subjects; and 1.30 (1.04-1.61), 1.20 (0.96-1.50), 1.33 (1.07-1.66), and 1.57 (1.26-1.95) for all subjects. The correlation between SUA and the prevalence of PVC was significant in all subjects and in male subjects, but not in female subjects. We demonstrated that SUA was apparently associated with the prevalence of PVC. The significant relationship between SUA and PVC identified in male subjects suggests the potential involvement of a gender-specific mechanism. Prospective studies are needed to further corroborate our results.

Measurement of plasma norepinephrine and 3,4-dihydroxyphenylglycol: method development for a translational research study

Objective

Norepinephrine (NE), a sympathetic neurotransmitter, is often measured in plasma as an index of sympathetic activity. To better understand NE dynamics, it is important to measure its principal metabolite, 3,4-dihydroxyphenylglycol (DHPG), concurrently. Our aim was to present a method, developed in the course of a translational research study, to measure NE and DHPG in human plasma using high performance liquid chromatography with electrochemical detection (HPLC-ED).

Results

After pre-purifying plasma samples by alumina extraction, we used HPLC-ED to separate and quantify NE and DHPG. In order to remove uric acid, which co-eluted with DHPG, a sodium bicarbonate wash was added to the alumina extraction procedure, and we oxidized the column eluates followed by reduction because catechols are reversibly oxidized whereas uric acid is irreversibly oxidized. Average recoveries of plasma NE and DHPG were 35.3 ± 1.0% and 16.3 ± 1.1%, respectively, and there was no detectable uric acid. Our estimated detection limits for NE and DHPG were approximately 85 pg/mL (0.5 pmol/mL) and 165 pg/mL (0.9 pmol/mL), respectively. The measurement of NE and DHPG in human plasma has wide applicability; thus, we describe a method to quantify plasma NE and DHPG in a laboratory setting as a useful tool for translational and clinical research.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3352-3) contains supplementary material, which is available to authorized users.

Elevated serum uric acid concentration at discharge confers additive prognostic value in elderly patients with acute heart failure

BACKGROUND AND AIMS

Elevated serum uric acid (sUA) concentrations have been associated with worse prognosis in heart failure (HF) but little is known about elderly patients. We aimed to assess long-term additive prognostic value of sUA in elderly patients hospitalized for HF.

METHODS AND RESULTS

Clinical and echocardiographic characteristics of 310 consecutive elderly patients hospitalized for HF were collected. During index period, 206 had sUA concentrations available, which were obtained within 24 h prior to discharge; 10 patients were lost to follow-up, leaving 196 patients available. Patients had a median age of 77 (IQR 69-83) years, and were mostly male (64.5%). sUA ranges for tertiles I-III were: 1.5-6.1, 6.2-8.3, and 8.4-18.9 mg/dl, respectively. During a median follow-up of 27 months (IQR 10.5-39.5), 122 combined events occurred (87 deaths and 73 HF rehospitalizations). Four-year event-free survival for the combined endpoint was 46 ± 7% for tertile I, 34 ± 7% for tertile II, and 21 ± 5% for tertile III (P = 0.001). By multivariable Cox backward analysis, sUA was retained as a significant predictor. Compared with the lowest sUA tertile, tertile III showed a strong association with outcome, also after adjustment for other predictors (HR 1.84, 95% CI 1.16-2.93; P = 0.01). Importantly, addition of sUA to the other significant predictors of outcome resulted in improved risk classification (net reclassification improvement 0.19, P = 0.017).

CONCLUSIONS

High sUA at discharge is a strong predictor of adverse outcome in elderly hospitalized for HF, and it significantly improves risk classification. Measuring sUA can be a simple and useful tool to identify high-risk elderly hospitalized for HF.

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

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

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

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

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

Prevalence of Hyperuricemia in Patients With Acute Heart Failure With Either Reduced or Preserved Ejection Fraction

The relation between uric acid (UA) and heart failure has been described; however, there is little detail concerning acute heart failure (AHF) in patients with reduced versus preserved ejection fraction heart failure (HFrEF, HFpEF). We studied 324 consecutive AHF patients screened from interventional Diur-HF Trial (NCT01441245) from January 2011 to February 2016, and divided into HFrEF (EF <50%) and HFpEF (EF ≥50%). We defined hyperuricemia as serum UA ≥7.0 mg/dL in men and ≥6 mg/dL in women. Patients were followed up for 6 months after discharge. The primary outcome was heart failure hospitalization or death. Among 173 HFrEF and 151 HFpEF cases, hyperuricemia was found in 43% and 57%, respectively (p = 0.01). Hyperuricemia was also more frequent in women (74% vs 60%; p = 0.008), those with diabetes (39% vs 19%; p <0.001), hypertension (62% vs 43%; p = 0.001), and atrial fibrillation (48% vs 34%; p = 0.01). In patients with HFrEF, univariate analysis found that hyperuricemia (hazard ratio [HR] 1.48, 95% confidence interval [CI] 1.02 to 2.15; p = 0.04) and congestion score ≥3 (HR 2.83, 95% CI 1.52 to 5.28; p <0.001) were associated with the primary end point; after adjustment, only congestion score ≥3 (HR 2.08, 95% CI 1.06 to 4.10; p = 0.03) confirmed this trend. Conversely, in patients with HFpEF, hyperuricemia was the only significant predictor of the primary end point both in univariate (HR 2.25, 95% CI 1.44 to 3.50; p <0.001) and multivariate analyses (HR 2.38, 95% CI 1.32 to 4.28; p = 0.004). In conclusion, in AHF hyperuricemia is common in both in HFrEF and in HFpEF. In the HFpEF subgroup, hyperuricemia was the only independent predictor of heart failure hospitalization or death.

[Independent risk factors for severe cardiovascular events in male patients with gout: Results of a 7-year prospective study]

AIM

To determine risk factors for severe cardiovascular (CV) events (CVEs) in male patients with crystal-verified gout.

SUBJECTS AND METHODS

251 male patients with crystal-verified gout were prospectively followed up in 2003 to 2013. The mean follow-up period was 6.9±2.0 years. New severe CVE cases and deaths were recorded. Logistic regression was used to analyze the impact of traditional and other risk factors and allopurinol use on the risk for severe CVEs.

RESULTS

32 patients died during the follow-up period. Severe CVEs were recorded in 58 (23.1%) patients; CVE deaths were notified in 22 (8.8%) patients. The risk of all severe CVEs was high for hypertension, increased serum high-sensitivity C-reactive protein (hs-CRP) level (>5 mg/l), ≥ stage III chronic kidney disease (CKD) (glomerular filtration rate, <60 ml/min/1.73 m2), alcohol intake (>20 g/day), coronary heart disease (CHD), and a family history of premature CHD. The risk of fatal CVEs was highest for elevated serum hs-CRP level, ≥ stage III CKD, a family history of premature CHD, hypercholesterolemia, upper quartile of serum uric acid levels (>552 µmol/l), and regular intake of allopurinol.

CONCLUSION

In addition to the traditional risk factors of CV catastrophes, the presence of chronic inflammation and the impact of high serum uric acid levels may explain the high frequency of CV catastrophes.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

Biomarcadores de função endotelial em doenças cardiovasculares: hipertensão

A incidência de hipertensão arterial sistêmica está aumentando mundialmente. Sua prevenção baseia-se na identificação dos hipertensos. Atualmente, biomarcadores são utilizados com fins de diagnosticar, estratificar e prognosticar doenças. Neste estudo, objetivou-se revisar artigos dos últimos cinco anos relacionados a biomarcadores nas doenças cardiovasculares. Pesquisaram-se dados de PubMed, SciELO, Science Direct e MEDLINE, mediante as palavras-chave: hipertensão arterial, biomarcadores cardiovasculares, óxido nítrico, função endotelial e dimetilarginina assimétrica. Os estudos levantados mostram que as doenças cardiovasculares possuem uma etiologia complexa. Neste artigo, evidenciaram-se interações entre o óxido nítrico e a dimetilarginina assimétrica na regulação, no metabolismo e na determinação dos níveis intracelulares, e reviram-se outros biomarcadores relacionados à hipertensão. Alguns estudos indicam os biomarcadores como uma ferramenta útil na predição de eventos cardíacos, e outros reportam que eles contribuem pouco para a avaliação. A seleção e combinação desses pode ser uma alternativa para validar o uso dos biomarcadores devido à pouca especificidade existente para diagnosticar a hipertensão.

Prognostic Significance of Hyperuricemia in Patients With Acute Heart Failure

Serum uric acid (UA) is associated with death and hospitalization in chronic heart failure (HF). However, UA in acute HF has not been well studied with respect to its relation to renal dysfunction and vascular congestion. We measured admission serum UA along with baseline variables in 281 patients with acute HF screened from the Loop Diuretics Administration and Acute Heart Failure (Diur-HF) trial. Hyperuricemia was defined as serum UA >7 mg/dl in men and >6 mg/dl in women. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate <60 ml/min/1.73 m(2) before hospital admission. Death or HF hospitalization at 6 months was the primary outcome. The mean UA concentration was 6.4 ± 2.5 mg/dl, and 121 patients (43.1%) were classified as hyperuricemic. UA values were significantly increased in patients with CKD compared to patients without CKD (6.8 ± 2.7 vs 6.1 ± 2.1 mg/dl; p = 0.02); however, UA was not associated with the development of acute kidney injury. Patients with hyperuricemia had greater degrees of pulmonary and systemic congestion than normouricemic patients (congestion score 3.5 vs 2.1, p <0.01). Hyperuricemia was associated with higher risk of death or HF rehospitalization (univariate hazard ratio 1.46 [1.02 to 2.10]; p = 0.04, multivariate hazard ratio 1.69 [1.16 to 2.45]; p = 0.005). In conclusion, hospitalized patients with acute HF, elevated UA levels were associated with both CKD and pulmonary congestion. After controlling for potential confounders, hyperuricemia was associated with rehospitalization and death at 6 months.

Serum uric acid is associated with cardiac diastolic dysfunction among women with preserved ejection fraction

Serum uric acid (SUA) is associated with the severity and prognosis of systolic heart failure. We investigated the potential association between SUA and cardiac diastolic dysfunction among total of 744 cardiac patients (202 women and 542 men) who had preserved left ventricular ejection fraction. Presence of diastolic dysfunction was assessed by echocardiographic data, plasma B-type natriuretic peptide concentration, and left ventricular hypertrophy. Univariate analysis showed that the prevalence of diastolic dysfunction increased with increasing SUA value in women, but not in men. When sex-nonspecific SUA quartiles were used, multivariate logistic regression analysis, among female patients who were not taking uric acid lowering medication, showed that the third (SUA, 5.7-6.4 mg) and the fourth (SUA, ≥6.5 mg/dl) SUA quartiles were associated with diastolic dysfunction with an odds ratio of 3.25 (P < 0.05) and 8.06 (P < 0.001), respectively, when compared with the first SUA quartile (≤4.7 mg/dl). When sex-specific SUA quartiles were used among these population, multivariate logistic regression analysis showed that the fourth SUA quartile (≥5.7 mg/dl) was associated with diastolic dysfunction with an odds ratio of 5.34 (P < 0.05) when compared with the first SUA quartile (≤4.1 mg/dl). By contrast, the relationship between SUA and diastolic dysfunction was not significant in men, irrespective of which of the sex-nonspecific or sex-specific SUA quartiles were used. These data indicated that among cardiac patients with preserved ejection fraction, SUA was significantly associated with diastolic dysfunction in women but not in men.

Relationship between serum uric acid and electrocardiographic alterations in a large sample of general population: data from the Brisighella Heart Study

INTRODUCTION

Serum uric acid (SUA) may contribute to the increased cardiovascular damage through direct injury to the endothelium and alteration of cardiovascular function.

AIM

To evaluate the association of SUA with the presence of the most recurrent electrographic alterations and with the length of the main ECG intervals in a large sample of general population.

METHODS

For this study, on the database of the Brisighella Heart Study, we evaluated the available data of 790 men and 849 women, excluding subjects affected by gout or taking antihyperuricemic agents, those taking drug increasing the QT interval and those using beta-blockers or non-dihydropyridine calcium channel blockers at the moment of the ECG registration. Multiple ascending stepwise regression analyses were carried out to determine the independent predictors of the predefined ECG alterations.

RESULTS

The prevalence of predefined ECG alterations was comparable between genders, with the exception of sinus bradicardia, left-anterior fascicular block, atrio-ventricular blocks and left ventricular hypertrophy (LVH), which appeared to be more frequent in men. The multivariate analysis revealed that SUA was associated to ischaemic alterations, LVH, sinus tachycardia and tachyarrhytmias. Age was associated to all evaluated ECG alterations beyond sinus tachycardia and LVH. Male sex was associated to sinus bradicardia, atrio-ventricular blocks, anterior-left fascicular block and LVH. Blood pressure was associated to different ECG alterations, but with clinically relevant OR with ischaemic alterations and LVH.

CONCLUSION

SUA level is related the prevalence of both organic and rhythm ECG alterations in a wide sample of general population.

Serum uric Acid as a marker of coronary calcification in patients with asymptomatic coronary artery disease with preserved left ventricular pump function

Objective. To evaluate the interrelation between serum uric acid and artery calcification in asymptomatic coronary artery disease subjects. Design and Methods. 126 subjects with previously documented asymptomatic coronary artery disease were enrolled in the study. Results. Mean value of serum uric acid level was 23.84 mmol/L (95% confidence interval (CI)  =  15.75-31.25 mmol/L). In multivariate Cox regression analysis, the results showed that serum uric acid levels (odds ratio (OR) = 1.42, 95% CI = 1.20-1.82; P < 0.001), osteopontin (OR = 1.14, 95% CI = 1.12-1.25; P < 0.001), osteoprotegerin (OR = 1.45, 95% CI  =  1.20-1.89; P < 0.001), type 2 diabetes mellitus (OR = 1.41, 95% CI  =  1.20-1.72; P < 0.001), and total cholesterol (OR = 1.13, 95% CI = 1.10-1.22; P < 0.001) were factors that independently associated with coronary artery calcification. The Cox models suggested that high quartile of serum uric acid level is very significant in predicting Agatston score index. In conclusion, we suggested that high quartile of serum uric acid level (cutoff point equaled 35.9 mmol/L) was a very significant predictor of coronary calcification examined by Agatston score index in subjects with asymptomatic coronary artery disease.