Patients with pulmonary arterial hypertension (PAH) experience symptoms such as shortness of breath, exhaustion, and lack of vitality—and often death within a short time after onset of the disease. Various methods of treatment can slow down the progression of the disease and improve symptoms, but no cure has yet been available.

The function of the vascular endothelium is threefold: ensure low-friction blood flow, regulate the diameter of the blood vessels, and adapt the distribution of the blood to the body’s requirements. The endothelium also controls blood vessel growth. In PAH, the blood vessels contract and narrow and the vessel walls thicken, leading to the obstruction of blood flow. The heart must pump harder to counteract this resistance, causing changes in the right ventricle, resulting in right heart failure.

This is a delicate system, balanced by just a few factors, and nitric oxide plays a central role. Scientists have been aware of the importance of NO as a regulator of the width of blood vessels and cell proliferation, according to Ralph Schermuley, a research group leader at the Max Planck Institute. The sudden decline in the production of nitric oxide by the endothelium plans an important role in the development of PAH.

Max Planck researchers and colleagues from the University of Giessen attempted to intervene in this system by having rats, in which PAH had been induced, repeatedly inhale a nasal spray containing NO over a period of 4 weeks.

“The effect was impressive. Not only was the disease progression halted, we were able to observe a clear improvement in all areas,” explains Soni Pullamsetti, the first author of the study. The normal function of the endothelium was restored, cell proliferation in the blood vessel walls decreased significantly, and the narrowing of the blood vessels reversed.

The researchers plan to carry out further research on the therapeutic potential of their findings, believing that treatment via a nasal spry would offer a relatively effortless form of therapy without possible severe side effects.

Sources: Max-Planck-Gesellschaft, AlphaGalileo Foundation.