Pulmonary hypertension reversed in mice

SAN DIEGO, Oct. 26 (UPI) -- U.S. scientists say they've reversed pulmonary arterial hypertension in mice by identifying a protein that promotes the illness in mice and humans.

The University of California-San Diego researchers said their discovery has implications for future drug therapies that might prevent the need for lung transplantation, which is currently the only cure for pulmonary arterial hypertension -- a form of high blood pressure in the lung's arteries.

Professor Patricia Thistlethwaite, who led the study, said her team identified a genetic pathway by which vascular smooth muscle cells associated with pulmonary arterial hypertension are switched on to proliferate by a receptor protein called Notch-3. With that finding, the researchers were able to block and reverse the pathway of disease in mice.

"(We) found pulmonary hypertension is characterized by overexpression of Notch-3 and the severity of the disease correlates with the amount of this protein in the lung," said Thistelthwaite. "We showed that a mouse model lacking this protein does not develop pulmonary hypertension, and, in addition, the disease can be effectively treated with an enzyme … which blocks Notch-3 activation."

Thistlethwaite said mice with pulmonary arterial hypertension that were treated with the enzyme showed reversal of the disease.

The research appears in the early online edition of the journal Nature Medicine.