Arterial compliance and its dynamics in obese adolescents

Area of Science:

• Cardiovascular Physiology
• Pediatric Endocrinology
• Vascular Biology

Background:

• Arterial compliance (AC) declines with age, a process potentially accelerated by obesity and atherosclerosis.
• Previous studies on obesity's impact on AC, often estimated by pulse wave velocity (PWV), have yielded conflicting results.
• Understanding AC in adolescents, considering obesity and physiological states, is crucial for cardiovascular health assessment.

Purpose of the Study:

• To compare arterial compliance (AC) in obese versus control adolescents.
• To evaluate AC across four distinct physiological states: supine rest, head-up tilt (HUT), supine recovery, and mental arithmetic (MA).
• To investigate the influence of obesity on AC, controlling for potential confounders like blood pressure.

Main Methods:

• Arterial compliance (AC) was assessed using a two-element Windkessel model, calculating the ratio of the time constant (t) to total peripheral resistance (TPR).
• Fifty healthy, normotensive adolescents (25 obese, 25 controls, matched for age and sex) participated.
• AC was measured during supine rest, HUT, recovery, and mental arithmetic (MA) to assess responses to different physiological conditions.

Main Results:

• Obese adolescents exhibited significantly higher AC values compared to controls across all tested physiological states.
• This increase in AC among obese subjects persisted even after adjusting for blood pressure.
• Pulse wave velocity (PWV) estimations corroborated the findings of increased AC in the obese group.

Conclusions:

• Arterial compliance (AC) is consistently elevated in young obese individuals across various physiological conditions.
• Both groups demonstrated similar AC responses to stress (HUT, MA), indicating preserved autonomic control of elastic arteries.
• Reduced TPR in obese subjects suggests arterial tree maturation differences or vasomotion changes may counteract atherosclerosis progression.