Abstract 246: Thoracic versus Abdominal Aortic Stiffness in Young and Old Non-Human Primates

We demonstrated that thoracic aortic stiffness is increased in aging monkeys, with the mechanism involving increased vascular smooth muscle cell (VSMC) stiffness. In view of the importance of increased abdominal aortic stiffness to greater incidence of abdominal aortic aneurysms, the goal of this investigation was to determine differences in thoracic vs. abdominal aortic stiffness in young and old monkeys (fascicularis and rhesus). Most prior studies on aortic stiffness have been conducted in vitro or in anesthetized animals with indirect measurements of stiffness. A novel feature of the current investigation was to measure aortic diameter and pressure instantaneously and continuously in chronically instrumented, conscious young (n=25, 5-12yrs) and old male (n=21, u003e24yrs) monkeys, instrumented with aortic pressure gauges and ultrasonic aortic diameter crystals on the thoracic and abdominal aorta. The aortic stiffness index, β[[Unable to Display Character: ]][[Unable to Display Character: ]...