UCP1 and cardiac hypertrophy: In vivo echocardiography revealed that aging UCP1−/− mice had comparable cardiac function as aging WT mice, as shown by hemodynamics, ventricular function, left ventricular internal diameter of diastolic and systolic, and heart volume, accompanied with similar gene expressions of myocardial hypertrophy and fibrotic markers between the two genotypes of mice (Figure S5A–H, Supporting Information).