Increased levels of the blood plasma protein endothelin-1 are linked to pulmonary hypertension in African-Americans, according to a large study exploring heart disease.
The findings, presented in the journal JAMA Cardiology in the study titled “Association of Elevated Plasma Endothelin-1 Levels With Pulmonary Hypertension, Mortality, and Heart Failure in African American Individuals,” demonstrated that levels of endothelin-1 might be used to identify people at risk for lung hypertension, allowing early treatment to prevent disease progression.
Although drugs blocking endothelin receptors, such as Tracleer (bosentan) and Opsumit (macitentan), are used to treat pulmonary arterial hypertension (PAH), where scientists have noted higher levels of the blood vessel factor, it is far from clear that endothelin-1 is linked to other types of lung hypertension.
Researchers at Providence Veterans Affairs Medical Center used data from the Jackson Heart Study, a heart disease study that focused on African-Americans living in Jackson, Mississippi. The study includes 3,223 individuals, providing plenty of data for researchers. In this group of people, 32.6% were men, and 6.7% had lung hypertension, and analyses showed that the higher endothelin-1 levels were, the higher the odds were of developing pulmonary hypertension.
Researchers could also see that higher levels of endothelin-1 were associated with a higher risk of heart failure and death. In fact, when they divided patients into four groups depending on the presence of lung hypertension and levels of the factor (high or low), those with lung hypertension and high endothelin-1 were found to have the worst survival.
Participants in the study suffered many other conditions — high blood pressure, obesity, and diabetes were common. The study identified several other factors linked to endothelin-1 levels, and some, such as age, smoking status, body mass index, heart disease, and lung function, impacted the relationship between the blood vessel factor and pulmonary hypertension.
Further analyses also showed that the link only really existed in patients with a history of coronary heart disease and those who had never smoked, but not in current or former smokers. Also, in patients who had obstructed airways there was a relationship between endothelin-1 levels and pulmonary hypertension, but not in those with normal lung function.
“Elevated plasma endothelin-1 levels, especially associated with an elevated pulmonary artery systolic pressure on echocardiogram, may identify an at-risk population that could be evaluated for targeted prevention and management strategies in future studies,” the research team concluded.