Thyroid hormones induce unique and potentially beneficial changes in cardiac myocyte shape in hypertensive rats near heart failure.

We examined the effects of thyroid hormones (THs) on left ventricular (LV) function and myocyte remodeling in rats with spontaneously hypertensive heart failure (SHHF). SHHF rats were treated with three different TH doses from 20-21 mo of age. In terminal experiments, LV function (as determined by echocardiography and catheterization) and isolated myocyte shape were examined in SHHF rat groups and age-matched Wistar-Furth control animals.

Temporal regression of myocyte hypertrophy in hypertensive, heart failure-prone rats treated with an AT1-receptor antagonist.

Background: A recent study showed reverse remodeling of left ventricular myocyte shape when the type 1 angiotensin II (AT1)-receptor antagonist L-158,809 was administered to spontaneously hypertensive heart failure (SHHF) rats 4 months before the onset of failure. The aim of this study was to characterize temporally early treatment-induced reverse remodeling at the organ and cellular level by echocardiography and morphometry of isolated left ventricular myocytes.

Methods And Results: L-158,809 was administered to 9-month-old SHHF rats.