Central Artery Hemodynamics in Angiotensin II-Induced Hypertension and Effects of Anesthesia

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Animal Models in Hypertension Research

Background:

• Systemic hypertension is a major risk factor for cardiovascular, neurovascular, and renovascular diseases.
• Central artery stiffness is a key factor in hypertension, linking vascular mechanics and hemodynamics.
• Mice are vital models for hypertension research, but hemodynamic data is typically collected under anesthesia.

Purpose of the Study:

• To develop and validate an experimental-computational workflow to estimate awake cardiovascular conditions from anesthetized data in mice.
• To quantify the effects of chronic angiotensin II-induced hypertension on cardiovascular hemodynamics and vascular properties in awake wild-type mice.

Main Methods:

• Developed a novel experimental-computational workflow to bridge anesthetized and awake physiological states.
• Utilized chronic angiotensin II infusion to induce hypertension in wild-type mice.
• Compared hemodynamic and vascular property changes between hypertensive and normotensive groups under simulated awake conditions.

Main Results:

• Anesthesia significantly impacted hemodynamics, particularly in angiotensin II-infused mice, leading to unexpected results when comparing anesthetized data.
• Awake simulations revealed that angiotensin II infusion increased in vivo vascular stiffness in the descending thoracic and suprarenal abdominal aorta.
• Hypertension led to increased pulse pressure in the distal aorta and characterized regionally varying vascular remodeling effects.

Conclusions:

• The developed workflow accurately estimates in vivo cardiovascular conditions, overcoming anesthesia-induced artifacts.
• Chronic angiotensin II infusion causes significant vascular remodeling and altered hemodynamics in mice, consistent with hypertension pathophysiology.
• This approach enables a better characterization of hypertension's impact on vascular structure, properties, and hemodynamics in a mouse model.