Relationship between Arterial Stiffness and Heart Rate Recovery in Apparently Healthy Adults

Ding-Yu Fei1, Ross Arena2, James A Arrowood3, Kenneth A Kraft41Department of Biomedical Engineering, 2Department of Physical Therapy, 3Department of Internal Medicine, Division of Cardiology, 4Department of Radiology, Virginia Commonwealth University, Richmond, VA, USAIntroduction: Arterial stiffness and heart rate recovery (HRR) following exercise testing have emerged as variables holding significant prognostic value in a number of populations. The purpose of the present study is to examine the relationship between arterial stiffness and HRR in a group of apparently healthy subjects.Methods: Two hundred and nine apparently healthy subjects underwent maximal exercise testing. Heart rate at one and two minutes post exercise was subtracted from maximal heart rate during the exercise test to produce two measures of heart rate recovery. Aortic wave velocity, in meters per second, was obtained via a new magnetic resonance technique. Results: Pearson Product Moment Correlation analysis revealed a significant correlation between aortic wave velocity and heart rate recovery. Stepwise linear regression analysis revealed that age, maximal aerobic capacity, heart rate recovery at one minute, and diastolic blood pressure were all significant predictors of aortic wave velocity (r = 0.63, r2 = 0.40, p < 0.001). Conclusions: The results of the present study indicate that heart rate recovery is significantly correlated with a measure of large artery stiffness and adds predictive value to other clinical variables. This analysis provides further evidence that assessment of heart rate recovery should be considered in subjects undergoing exercise testing in clinical practice.Keywords: exercise testing, oxygen consumption, aortic wave velocit

Cathelicidin-like Helminth Defence Molecules (HDMs) Absence of Cytotoxic, Anti-microbial and Anti-protozoan Activities Imply a Specific Adaptation to Immune Modulation

Host defence peptides (HDPs) are expressed throughout the animal and plant kingdoms. They have multifunctional roles in the defence against infectious agents of mammals, possessing both bactericidal and immune-modulatory activities. We have identified a novel family of molecules secreted by helminth parasites (helminth defence molecules; HDMs) that exhibit similar structural and biochemical characteristics to the HDPs. Here, we have analyzed the functional activities of four HDMs derived from Schistosoma mansoni and Fasciola hepatica and compared them to human, mouse, bovine and sheep HDPs. Unlike the mammalian HDPs the helminth-derived HDMs show no antimicrobial activity and are non-cytotoxic to mammalian cells (macrophages and red blood cells). However, both the mammalian- and helminth-derived peptides suppress the activation of macrophages by microbial stimuli and alter the response of B cells to cytokine stimulation. Therefore, we hypothesise that HDMs represent a novel family of HDPs that evolved to regulate the immune responses of their mammalian hosts by retaining potent immune modulatory properties without causing deleterious cytotoxic effects. © 2013 Thivierge et al