Washington, Sept 17 : Sex hormone estrogen could help reverse the progression of advanced pulmonary hypertension to heart failure and can restore lung and ventricle structure and function, according to a new study.

Researchers at UCLA have found that by treating rats with severe pulmonary hypertension with low doses of estrogen, they were able to prevent the disease from progressing to right-ventricular heart failure; this did not happen in untreated rats.

Systolic blood pressure and ejection fraction - the volume of blood being pumped out of the heart's right chamber with each heart beat - also improved.

Tests showed that lung weight, which can increase with the disease and resulting heart-ventricle enlargement, was also corrected. After 10 days of estrogen treatment, function returned to an almost normal state.

The researchers stopped the estrogen therapy after 10 days but continued to observe some of the treated rats.

They tracked the continued improvement and found almost full restoration of systolic blood pressure and ejection fraction to normal levels after an additional 12 days.

"We were surprised to find this continued benefit, even after we stopped the estrogen treatment," said the study's first author, Dr. Soban Umar, a UCLA Department of Anesthesiology researcher.

"These findings suggest that even short-term estrogen therapy may suffice to reverse the disease," he added.

All rats with severe pulmonary hypertension that were treated with estrogen survived by the study's end. Only 25 percent of the untreated rats survived.

The study was recently published in the American Journal of Respiratory and Critical Care Medicine. (ANI)