AGED MICE EXHIBIT CARDIAC ELECTROPHYSIOLOGICAL DYSFUNCTIONS AND IMPAIRED VASCULAR REACTIVITY

Aging is a natural process that affects almost all living beings, and is characterized by the deterioration of the physiological mechanisms that regulate the milieu interieur. The resulting allostatic overload leads to systemic dysfunctions, especially a decline in the cardiovascular homeostasis. Aged hearts exhibit myocardial stiffening, increased interstitial fibrosis due to collagen deposition and cardiomyocyte hypertrophy. These factors together result in loss of compliance and lower conductance of electrical current through the tissue. Aged vasculature also exhibits progressive collagen deposition, stiffening, and calcification. Additionally, there is an increase in oxidative stress and endothelial dysfunction, characterized by the inability to release nitric oxide (NO), resulting in loss of vessel compliance.