Kidney Function, Nutritional Status, and the Left Ventricle Dysfunction Are Associated with Serum Uric Acid Levels in Patients with Heart Failure with Reduced Ejection Fraction.

OBJECTIVE: The aim of this study was to assess the role of potential factors explaining variability of serum uric acid (SUA) levels in patients with chronic heart failure with reduced ejection fraction (HFrEF) not receiving xanthine oxidase inhibitors and acetylsalicylic acid, with multivariate adaptive regression splines and fuzzy c-regression models. MATERIAL AND METHODS: Between 1998 and 2010, we prospectively enrolled 294 patients (44 females, 250 males; mean age 43.1±11.6 years) not receiving allopurinol or febuxostat, who underwent right ventricular endomyocardial biopsy due to unexplained HFrEF (duration of symptoms ≥6 months) with New York Heart Association functional class II and III and decreased left ventricular ejection fraction <40% in radionuclide study. The following factors were analyzed: left ventricular ejection fraction, concentrations of serum creatinine, high-sensitivity C-reactive protein, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), SUA, glucose, total cholesterol, HDL and LDL fractions of cholesterol, triglycerides, fibrate, D-dimers, and medication. Multivariate Adaptive Regression Splines, local polynomial smoothing with Epanechnikov kernel function as well as the Time Domain Constrained Fuzzy c-Regression Models were used. RESULTS: SUA concentration variability was explained by BMI, eGFR values, serum NT-pro BNP levels and the use of thiazide diuretics. The SUA declined with eGFR and increased with BMI values, serum NT-proBNP levels and the use of thiazide diuretics. A weak negative correlation between log10(SUA) levels and the LVEF was found (r=-0.130; p<0.05). CONCLUSIONS: Kidney function, nutritional status, the use of thiazide diuretics and the severity of left ventricle dysfunction reflected by serum NT-proBNP levels explain the serum uric acid levels variability in patients with HFrEF.

Plasma Level of Retinol-Binding Protein 4, N-Terminal proBNP and Renal Function in Older Patients Hospitalized for Heart Failure.

BACKGROUND/AIM: Elevated plasma concentration of retinol-binding protein 4 (RBP4) has recently emerged as a potential new risk factor for cardiovascular diseases, including hypertension (HT) and coronary artery disease (CAD). Limited data suggest that RBP4 promotes inflammatory damage to cardiomyocytes and participates in the development of heart failure (HF). This study aimed to analyze the relationship between concentrations of plasma RBP4 and serum N-terminal proBNP (NT-proBNP), a powerful biomarker of left ventricle dysfunction, in the older Polish population. METHODS: The study sample consisted of 2,826 (1,487 men) participants of the PolSenior study, aged 65 years and older, including a subgroup hospitalized for HF (n = 282). In all subjects, plasma concentrations of RBP4, interleukin-6 (IL-6), serum level of NT-proBNP, and hs-CRP were measured. Additionally, BMI, estimated glomerular filtration rate (eGFR), and HOMA-IR were calculated. The prevalence of HT, CAD, atrial fibrillation (AF), and medication were considered as potential confounders. RESULTS: Similar RBP4 levels were found in subjects with NT-proBNP < 125 and ≥125 ng/mL, with and without AF, and in the subgroups hospitalized for HF with and without AF. Regression analysis revealed no association between log10(NT-proBNP) and log10(RBP4). Plasma levels of RBP4 were increased by HT occurrence and diuretic therapy, while diminished with regard to female gender, age, eGFR values, AF, and IL-6 levels. CONCLUSION: Our results show that RBP4 is affected by GFR but cannot be considered as an independent biomarker of heart muscle dysfunction.

Increased plasma RBP4 concentration in older hypertensives is related to the decreased kidney function and the number of antihypertensive drugs-results from the PolSenior substudy.

Increased plasma retinol-binding protein 4 (RBP4), a novel adipokine, has been associated in previous studies with obesity, type 2 diabetes, dyslipidemia, hypertension (HT), atherosclerosis, and coronary artery disease. This study aimed to analyze the relationship between HT occurrence and its treatment, and plasma RBP4 concentrations in the older polish population. The study sample consisted of 1728 (890 men and 838 women) PolSenior study participants aged 65 years and older with available plasma samples and NT-proBNP values below 2000 pg/mL. The analysis included body mass index, waist circumference, blood pressure, antihypertensive medication, estimated glomerular filtration rate, serum glucose and insulin (and the homeostatic model assessment of insulin resistance), and plasma RBP4 levels. RBP4 plasma concentrations were higher in hypertensive (N = 645) than normotensive (N = 236) men (43.4 [30.4-64.8] vs. 38.1 [27.1-54.4] ng/mL, respectively; P < .01) but not in women (44.6 [29.6-63.5] vs. 40.7 [29.1-58.1] ng/mL, respectively; P = .21). In the subanalysis, higher plasma RBP4 levels were observed in women with treated than untreated HT and in subjects taking four of more antihypertensive drugs. The linear regression shown that estimated glomerular filtration rate (ß = -0.015), thiazide diuretics (ß = 0.041), and α-blockers (ß = 0.049) were explaining log10RBP4 plasma levels variability in the study group. Older male Caucasians with HT are characterized by elevated plasma RBP4 levels. This increase is proportional to the number of antihypertensive drugs and decreased glomerular filtration rate. Among the antihypertensive drugs, only thiazide diuretics and α-blockers had a significant influence on RBP4 levels.