Abstract P150: Estrogen Protects Against and Reverses Adverse Ventricular Remodeling in Pulmonary Hypertension-Induced Right Ventricular Failure
Pulmonary hypertension (PH) leads to right-ventricular failure (RVF). RVF is characterized by adverse RV remodeling including hypertrophy and changes in the cardiac Extracellular Matrix (ECM) such as fibrosis and re-expression of cardiac fetal genes. Among the potentially re-expressed genes are the novel ECM interacting proteins Osteopontin (OPN) and Osteocalcin (OCN).
Gender differences found in experimental PH are attributed to protective effects of Estrogen (E2). We hypothesize that gender differences observed in experimental PH are partially due to the effects of E2 on the cardiac ECM, and that exogenous E2 may be able to reverse adverse RV remodeling.
Male and female rats received single monocrotaline (MCT, 60mg/kg) injection. Some rats were given E2 (42.5μg/kg/day) from day 21–30. Saline treated rats were controls. Cardiopulmonary hemodynamics were serially monitored and RV pressures (RVP) were recorded terminally. RV fibrosis was assessed by trichrome staining. Gene expression was determined by RT PCR and plasma OPN by ELISA.
All rats developed PH by day 21 and RVF by day 30. Male rats developed more severe PH-induced RVF than females (RVP=70 vs. 41.5±5 mmHg; RV/(LV+IVS)= 0.69±0.07 vs. 0.47±0.04; RVEF = 30.4±1.8 vs. 42.8±2% resp., all p<0.05). Males also revealed more severe RV fibrosis and greater re-expression of OPN (4.5 fold vs. females, p<0.05) and OCN (2-fold vs. females, p<0.05). Plasma OPN was also elevated in RVF males (1.00±0.11 in control to 1.47±0.18 pg/ml, p<0.05) but not RVF females (0.848±0.18 in control to 0.859±0.294 pg/ml, p=ns).
Since females experienced less severe RV remodeling than males, MCT injected males were treated with exogenous E2 from day 21–30. Some E2 treated male rats were sacrificed at day 30, and some were kept an additional 12 days after E2-withdrawal (E2-W group). E2 reversed PH-induced RVF (RVP=38mmHg; RV/(LV+IVS) = 0.28±0.03; RVEF=61.5±0.8%, all p<0.05 vs. male RVF) and fibrosis. OPN and OCN were fully restored following E2 withdrawal by day 42. E2 therapy also restored circulating OPN levels (p<0.05 vs. RVF) showing that OPN has potential value as a plasma marker for PH-induced RV failure.
These results suggest that E2 protects against adverse RV remodeling in females, and reverses adverse RV remodeling in males.
- © 2011 by American Heart Association, Inc.