Serum uric acid levels correlate with left atrial function and systolic right ventricular function in patients with newly diagnosed heart failure: the hellenic heart failure study

Impaired Myocardial Energetics Causes Mechanical Dysfunction in Decompensated Failing Hearts

Cardiac mechanical function is supported by ATP hydrolysis, which provides the chemical-free energy to drive the molecular processes underlying cardiac pumping. Physiological rates of myocardial ATP consumption require the heart to resynthesize its entire ATP pool several times per minute. In the failing heart, cardiomyocyte metabolic dysfunction leads to a reduction in the capacity for ATP synthesis and associated free energy to drive cellular processes. Yet it remains unclear if and how metabolic/energetic dysfunction that occurs during heart failure affects mechanical function of the heart. We hypothesize that changes in phosphate metabolite concentrations (ATP, ADP, inorganic phosphate) that are associated with decompensation and failure have direct roles in impeding contractile function of the myocardium in heart failure, contributing to the whole-body phenotype. To test this hypothesis, a transverse aortic constriction (TAC) rat model of pressure overload, hypertrophy, and decompensation was used to assess relationships between metrics of whole-organ pump function and myocardial energetic state. A multiscale computational model of cardiac mechanoenergetic coupling was used to identify and quantify the contribution of metabolic dysfunction to observed mechanical dysfunction. Results show an overall reduction in capacity for oxidative ATP synthesis fueled by either fatty acid or carbohydrate substrates as well as a reduction in total levels of adenine nucleotides and creatine in myocardium from TAC animals compared to sham-operated controls. Changes in phosphate metabolite levels in the TAC rats are correlated with impaired mechanical function, consistent with the overall hypothesis. Furthermore, computational analysis of myocardial metabolism and contractile dynamics predicts that increased levels of inorganic phosphate in TAC compared to control animals kinetically impair the myosin ATPase crossbridge cycle in decompensated hypertrophy/heart failure.

Hyperuricemia Is Associated with Left Ventricular Dysfunction and Inappropriate Left Ventricular Mass in Chronic Kidney Disease

Background. Hyperuricemia is common in patients with chronic kidney disease (CKD), and this may lead to poor cardiovascular (CV) outcomes. The aim of this cross-sectional study was to assess associations among serum uric acid (UA) and echocardiographic parameters, ankle-brachial index (ABI), and brachial-ankle pulse wave velocity (baPWV) in patients with CKD. Methods. A total of 418 patients with CKD were included. The echocardiographic measurements included left atrial diameter (LAD), left ventricular ejection fraction (LVEF) and the ratio of observed to predict left ventricular mass (LVM). ABI, baPWV and medical records were obtained. Results. Multivariable forward logistic regression analysis showed that a high UA level was significantly associated with LAD > 47 mm (odds ratio [OR], 1.329; p = 0.002), observed/predicted LVM > 128% (OR, 1.198; p = 0.008) and LVEF < 50% (OR, 1.316; p = 0.002). No significant associations were found between UA and ABI < 0.9 or baPWV > 1822 cm/s. Multivariate stepwise linear regression analysis showed that a high UA level correlated with high LAD (unstandardized coefficient β, 0.767; p < 0.001), high observed/predicted LVM (unstandardized coefficient β, 4.791; p < 0.001) and low LVEF (unstandardized coefficient β, −1.126; p = 0.001). No significant associations between UA and low ABI and high baPWV were found. Conclusion. A high serum UA level was associated with a high LAD, high observed/predicted LVM and low LVEF in the patients with CKD. A high serum UA level may be correlated with abnormal echocardiographic parameters in patients with stage 3–5 CKD.

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.

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.

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

There is a need for a cost-effective prognostic biomarker in heart failure (HF). Substantial evidence suggests that uric acid (UA) is an independent marker for adverse prognosis in acute and chronic HF of varying severity. Whether UA is a merely a marker of poor prognosis or is an active participant in disease pathogenesis is currently unknown. In the setting of HF, at least two different processes can be responsible for increased UA: increased production, which may result from oxidative stress, and decreased excretion due to renal insufficiency, which can be a consequence of cardio-renal syndrome, renal congestion, or comorbidities. While pioneer studies have raised the possibility of preventing HF through the use of UA lowering agents, namely xanthine oxidase inhibitors and uricosurics, the literature is still conflicting on whether the reduction in UA will result in a measurable clinical benefit. In this review, we examine the evidence relating UA to HF prognosis, the mechanisms that contribute to increased UA levels in HF, and future novel treatments aimed at reducing UA levels.

Relation of elevated serum uric acid levels to incidence of atrial fibrillation in patients with type 2 diabetes mellitus

The association between serum uric acid (SUA) levels and atrial fibrillation (AF) is currently poorly known. We examined the association between SUA levels and risk of incident AF in patients with type 2 diabetes mellitus. We followed for 10 years a random sample of 400 type 2 diabetic outpatients, who were free from AF at baseline. A standard 12-lead electrocardiography was undertaken annually and a diagnosis of incident AF was confirmed in affected participants by a single cardiologist. Over 10 years, there were 42 incident AF cases (cumulative incidence of 10.5%). Elevated SUA level was associated with an increased risk of incident AF (odds ratio 2.43, 95% confidence interval 1.8 to 3.4, p <0.0001 for each 1-SD increase in SUA level). Adjustments for age, gender, body mass index, hypertension, chronic kidney disease, electrocardiographic features (left ventricular hypertrophy and PR interval), and use of diuretics and allopurinol did not attenuate the association between SUA and incident AF (adjusted odds ratio 2.44, 95% confidence interval 1.6 to 3.9, p <0.0001). Further adjustment for variables that were included in the 10-year Framingham Heart Study-derived AF risk score did not appreciably weaken this association. Results remained unchanged even when SUA was modeled as a categorical variable (stratifying by either SUA median or hyperuricemia), and when patients with previous coronary heart disease or heart failure were excluded from analysis. In conclusion, our findings suggest that elevated SUA levels are strongly associated with an increased incidence of AF in patients with type 2 diabetes mellitus even after adjustment for multiple clinical risk factors for AF.

Baseline and 6-Week follow-up levels of PAF and activity of its metabolic enzymes in patients with heart failure and healthy volunteers--a pilot study

This study aimed at evaluating the changes in platelet-activating factor (PAF) and its metabolic enzymes over a 6-week follow-up period in patients with newly diagnosed heart failure ([HF] n = 12) compared with age-, sex-, and BMI-matched apparently healthy volunteers (n = 10). The PAF, its key biosynthetic enzymes (lyso-PAF acetyltransferase [lyso-PAF-AT] and dithiothreitol [DTT]-insensitive CDP choline: 1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase [PAF-CPT]), and its catabolic isoenzymes (PAF-acetylhydrolase [PAF-AH] and lipoprotein-associated phospholipase A2 [Lp-PLA2]) were measured in serum and leukocytes of participants. At baseline, patients with HF had lower median activities of lyso-PAF-AT (P < .001) and PAF-CPT (P = .07) in parallel with PAF levels (P = .05) and higher activities of PAF-AH (P = .02) and Lp-PLA2 (P < .001) than controls. At follow-up, PAF-CPT and PAF levels marginally increased (P = .1), lyso-PAF-AT (P < .001) remained downregulated, while PAF-AH (P = .004) and Lp-PLA2 (P < .001) remained elevated compared with the controls. Newly diagnosed patients with HF under drug treatment have an affected profile of PAF biosynthetic enzymes and especially lyso-PAF-AT.

Long-term adherence to the Mediterranean diet reduces the prevalence of hyperuricaemia in elderly individuals, without known cardiovascular disease: the Ikaria study

BACKGROUND

The purpose of this study was to evaluate the impact of adherence to Mediterranean diet on serum uric acid (UA) levels in elderly individuals, without known cardiovascular disease.

METHODS

During 2009, 281 females (75±6 years old) and 257 males (75±7 years old) permanent inhabitants of the island, were voluntarily enrolled. A diet score that assesses the inherent characteristics of the Mediterranean diet (MedDietScore, range 0-55) was applied. Serum levels of UA were determined using an enzymatic colorimetric test through the uricase-peroxidase method. Hyperuricaemia was defined as UA>7 mg/dL in males and 6 mg/dL in females.

RESULTS

Prevalence of hyperuricaemia was 34% in males and 25% in females (p=0.02). Mean level of adherence to the Mediterranean diet was 35±2. Linear regression analysis revealed that MedDietScore was inversely associated with UA levels (b±SE: -1.48±0.17, p<0.001) in the overall sample, after controlling for hypertension, hypercholesterolemia, diabetes mellitus, creatinine clearance, physical activity, and coffee consumption. When the analysis was stratified by gender, MedDietScore was inversely associated with UA levels in males (b±SE: -1.10±0.42, p=0.009), but not in females (b±SE: 0.04±0.41, p=0.92).

CONCLUSION

Another cardioprotective effect of Mediterranean diet was revealed, through the modification of UA levels in elderly individuals. The potential different effect size as regards the relationship between diet and UA levels between genders, deserves further investigation.

Renal function, cardiovascular disease risk factors' prevalence and 5-year disease incidence; the role of diet, exercise, lipids and inflammation markers: the ATTICA study

BACKGROUND

We aimed to evaluate the association between renal function and various cardiovascular disease (CVD) risk factors, as well as 5-year incidence of CVD, in a sample of CVD free adults.

METHODS

(i) Cross-sectional information from n = 1975. Greek men and women (>18 years) without CVD and hypertension at baseline examination and (ii) 5-year (2001-06) survival data from n = 2101 individuals without CVD at baseline, all participants in the ATTICA study, were analysed in this work. Kidney function was quantified by the baseline estimated creatinine clearance rate (C(cr)), using the Cockcroft-Gault formula and the National Kidney Foundation recommendations. Outcome of interest was the development of CVD that was defined according to WHO-ICD-10 criteria.

RESULTS

At baseline, the prevalence of moderate-to-severe renal dysfunction (i.e. C(cr) < 60) was 2.8% in males and 7.7% in females. Physical activity status, cigarette smoking, hypercholesterolemia and homocysteine levels and greater adherence to the Mediterranean diet were inversely associated with C(cr) rate (P < 0.05), while no association was found with history of diabetes. During the 5-year follow-up, people with moderate-to-severe renal dysfunction as compared with normal, had 3.21 times higher CVD risk [95% confidence interval (CI) 1.98-5.19], after adjusting for history of hypertension (hazard ratio = 2.15, 95% CI 1.48-3.11), hypercholesterolemia (1.37, 0.98-1.98), diabetes (3.28, 2.15-5.00), smoking habits (0.89, 0.60-1.32) and physical activity status (0.86, 0.56-1.21).

CONCLUSION

Renal function seems to be associated with the levels of lifestyle and bio-clinical CVD risk factors and contribute to the long-term incidence of cardiac events. Public health care practitioners should take into account renal function in better preventing the burden of CVD at individual, and population level, as well.

Platelet activating factor (PAF) and activity of its biosynthetic and catabolic enzymes in blood and leukocytes of male patients with newly diagnosed heart failure

OBJECTIVES

To evaluate platelet activating factor (PAF) levels, its metabolic enzymes activity and its associations with other inflammatory markers in heart failure (HF) patients.

DESIGN AND METHODS

PAF, and two of its key biosynthetic enzymes [lyso-PAF acetyltransferase (lyso-PAF-AT) and DTT-insensitive CDP-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT)] along with its catabolic enzymes [PAF-acetylhydrolase (PAF-AH) and lipoprotein-associated phospholipase-A(2) (Lp-PLA(2))] were measured in serum and leukocytes of twelve newly diagnosed male HF patients. Serum CRP, TNF-alpha, IL-6, sCD14 and CD40L were also determined.

RESULTS

PAF ranged from 0.03 to 5.6 pmol/mL. Median lyso-PAF-AT, PAF-CPT, PAF-AH and Lp-PLA(2) activities were 4.1, 68.42, 644.44 pmol/min/mg protein and 51.42 pmol/min/microL correspondingly. Lyso-PAF-AT and PAF-CPT activities positively correlated with CRP, IL-6 and with each other, whereas PAF-CPT activity correlated with sCD14 and CD40L (P<0.05).

CONCLUSIONS

PAF's biosynthetic enzyme activities correlated with inflammatory and immunologic molecules, which are activated in HF. Our study indicates a potential role of PAF in HF patients.