Inverse relationship between aldosterone and large artery compliance in chronically treated heart failure patients

Aims The purpose of this study was to examine, in chronically treated heart failure patients vs control subjects, the influence of neurohumoral activation and aldosterone escape on arterial elastic behaviour, assessed by noninvasive mathematical lumped-parameter modelling of the compliance of the arterial system. Methods and Results Radial arterial pulse waves were recorded non-invasively for 30 s with an arterial tonometer sensor array in 13 chronic heart failure patients (mean age, 59 +/- 2.5 years) in New York Heart Association class II. The patients had been taking digoxin, furosemide, captopril and aspirin for more than 3 months. Thirteen healthy subjects (mean age, 50 +/- 4.0 years) acted as controls. Compliance of the proximal (aorta and major branches, C1) and distal parts (C2) of the circulation were derived from a third order four-element modified Windkessel model which can reproduce arterial pressure waveforms, including both exponential and oscillatory sections. Active renin, angiotensin II and aldosterone levels were determined on venous blood samples in the supine position and after 30 min active standing. There was decreased proximal (C1, 1.51 +/- 0.11 ml . mmHg(-1), P<0.01) and distal (C2, 0050+/-0.011 ml . mmHg(-1)) arterial compliance in the chronic heart failure patients vs controls (C1, 1.71 +/- 0.16 ml. mmHg(-1); C2, 0.054 +/- 0.006 ml . mmHg(-1)). The chronic heart failure patients were characterized by an aldosterone escape phenomenon which was inversely correlated with the proximal arterial compliance in both supine (r= -0.795, P=0.002) and standing (r= -0.628, P=0.029) positions. Conclusions In chronically treated heart failure patients with full angiotensin-converting enzyme-inhibition and diuretics, there is decreased compliance of the aorta and its major branches, which is inversely correlated with the aldosterone escape phenomenon

In vitro and in vivo assessment of phage therapy against Staphylococcus aureus causing bovine mastitis.

The aim of this study was to assess the efficacy of lytic bacteriophages on Staphylococcus aureus causing bovine mastitis, by in vitro and in vivo assays using Galleria mellonella and murine mastitis models. Methods: Between May and December 2016, ten S. aureus (five methicillin-resistant and five methicillinsensitive) isolates were isolated from milk samples of cattle with mastitis in Belgium and Norway. The isolates were assessed in vitro for their susceptibility to four lytic bacteriophages (Romulus, Remus, ISP and DSM105264) and subsequently in vivo in G. mellonella larvae and in murine mastitis model. Results: Romulus, Remus and ISP showed a lytic activity against the S. aureus isolates in vitro. A larvae survival rate below 50% was observed at 4 days post-inoculation (DPI) in the groups infected with a methicillin-sensitive S. aureus isolate and treated with these three phages in vivo. An incomplete recovery of the mouse mastitis was observed at 48 h post-inoculation (HPI) in the groups infected and treated with the ISP phage in vivo. Conclusions: The observations are much more pronounced statistically between the infected- phosphate buffered saline (PBS)-treated and infected-phage-treated groups in G. mellonella and the murine mastitis model demonstrating an effect of the phages against S. aureus associated with bovine mastitis