The serum concentration of brain­derived neurotrophic factor is lower in ambulatory and clinically stable patients with more advanced systolic heart failure.

INTRODUCTION: Brain­derived neurotrophic factor (BDNF) is decreased in heart failure (HF), but whether serum BDNF concentration is related to the severity of HF with reduced left ventricular (LV) ejection fraction (LVEF) below 50% is uncertain. OBJECTIVES: We aimed to compare cardiac structure and function in ambulatory and clinically stable patients with HF and LVEF below 50% for lower and higher BDNF serum concentrations. PATIENTS AND METHODS: A total of 361 ambulatory patients with a compensated HF and LVEF below 50% underwent cardiac evaluation and measurement of serum BDNF and N­terminal pro-B­type natriuretic peptide (NT­proBNP). Patients from the lower (below median) and higher (equal to or above median) BDNF serum concentration groups were compared by analysis of covariance (ANCOVA) adjusted for age, sex, body mass index, resting heart rate, and systolic blood pressure. RESULTS: The patients were at a median age of 63.8 (interquartile range [IQR], 57.7-71.5) years and had a median LVEF of 31.0% (IQR, 23.0-37.4). Individuals with lower BDNF (<23.5 ng/ml) had significantly (P ≤0.05) more dilated right and left atria both before and after emptying, larger right ventricular end-diastolic diameter, LV end-systolic diameter, lower tricuspid annulus plane systolic excursion, shorter pulmonary acceleration time, higher mitral E to A waves ratio and mitral E wave to tissue Doppler e' wave ratio, and higher concentration of NT­proBNP. CONCLUSIONS: HF patients with LVEF below 50% and lower serum BDNF concentration present more advanced cardiac remodeling and dysfunction than individuals with higher BDNF. Potential mechanisms and clinical consequences of these findings require further investigation.

A Human Model of the Effects of an Instant Sheer Weight Loss on Cardiopulmonary Parameters during a Treadmill Run.

Exercise tolerance is limited in obesity and improves after weight reduction; therefore, we mutually compared the relative changes in exercise capacity variables during cardiopulmonary exercise tests (CPET) in a 12 kg sheer weight reduction model. Twenty healthy male runners underwent two CPETs: CPET1 with the actual body weight, which determined the anaerobic threshold (AT) and respiratory compensation point (RCP); and CPET2 during which the participants wore a +12 kg vest and ran at the AT speed set during the CPET1. Running after body weight reduction shifted the CPET parameters from the high-mixed aerobic-anaerobic (RCP) to the aerobic zone (AT), but these relative changes were not mutually similar. The most beneficial changes were found for breathing mechanics parameters (range 12-28%), followed by cardiovascular function (6-7%), gas exchange (5-6%), and the smallest for the respiratory exchange ratio (5%) representing the energy metabolism during exercise. There was no correlation between the extent of the relative body weight change (median value ~15%) and the changes in CPET parameters. Weight reduction improves exercise capacity and tolerance. However, the observed relative changes are not related to the magnitude of the body change nor comparable between various parameters characterizing the pulmonary and cardiovascular systems and energy metabolism.