Hydrogen sulfide (H2S) treatment maintains endothelial function in pulmonary arterial hypertension (PAH), according to a new study published in the European Journal of Pharmacology. It, therefore, has therapeutic potential for this disease.

The role of H2S in systemic circulation has already been examined. But its role in endothelium-dependent vasorelaxation has not been previously analyzed.

Here, a team of researchers from the Department of Pharmacology at Ege University, in Izmir, Turkey, led by Gulnur Sevin, PhD, used a monocrotaline-induced PAH rat model further to elucidate the potential effect of H2S in the disease.


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The researchers divided the rats into 4 groups: control, monocrotaline-treated, monocrotaline plus sodium sulfide (Na2S)-treated, and Na2S only-treated.

They found that monocrotaline increased right ventricular pressure and hypertrophy and that Na2S improved this. 

Furthermore, they showed that monocrotaline significantly reduced contractions induced by potassium chloride (KCl) and the relaxing responses to acetylcholine and L-cysteine in pulmonary arteries. It also reduced H2S production in the lungs and pulmonary arteries. When the animals were treated with Na2S as well as monocrotaline, these were increased.

Read more about the pathophysiology of PAH

H2S prevented the decrease in H2S levels induced by monocrotaline in the lungs as well as the pulmonary arteries, the researchers concluded. They said that H2S might have a protective effect against pulmonary dysfunction and improve exercise capacity.

They also showed that H2S could restore the balance between the relaxant and contractile pathways in the pulmonary arteries and have a cardiopulmonary protective effect.

“The treatments targeting H2S might be beneficial for promoting vascular alterations, ie endothelial dysfunction and impaired H2S-mediated relaxation in pulmonary arterial hypertension,” they concluded.

PAH is a complex disease characterized by structural and functional changes in the endothelial and smooth muscle cells in pulmonary arteries. To overcome these changes, blood pressure increases, which may lead to right ventricular failure over time.

Reference

Turhan K, Alan E, Yetik-Anacak G, Sevin G. H2S releasing sodium sulfide protects against pulmonary hypertension by improving vascular responses in monocrotaline-induced pulmonary hypertension. Eur J Pharmacol. 2022;5:175182. doi:10.1016/j.ejphar.2022.175182