Blood Protein Predictor of Heart Disease

Surfactant protein-D actually manufactured in lungs, not heart

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) It's long been known that chronic long inflammation was linked to an increased risk of cardiovascular disease. A new study indicates there is not only a connection, but a blood protein that acts as "a good predictor."

The research, reported in the European Heart Journal, demonstrates that a blood protein known as surfactant protein-D (SP-D), which is mainly synthesized in the lungs, can indicate heart disease.

"Keeping your lungs healthy helps protect your heart."

Investigators said SP-D was clearly associated with heart disease and fatalities in patients with coronary artery disease. SP-D's role in the lungs is to participate in the innate response to inhaled microorganisms and organic antigens by binding to their surface and prompting their clearance from the body.

Blood levels of SP-D increase when the lungs are inflamed and not working well such as a respiratory infection or the flu. They are also increased in smokers and those with chronic lung conditions like asthma. Levels of the protein are naturally low in healthy people, but the SP-D leaks from the lungs into the blood then into the circulation when the body is impaired.

Researchers aimed to determine whether or not circulating SP-D is related to cardiovascular fatalities in patients having coronary angiography, an imaging technique, for suspected coronary artery disease, and also second ex- and current smokers with mild airflow restriction but without a known history of heart disease.

Prior to the study there were no universally accepted predictors aside from lung function tests. Of the angiography patients who later died during follow up, 30 percent had significantly higher plasma SP-D than those who survived. It was also elevated among the group who had smoked.

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Review Date: 
June 9, 2011
Last Updated:
June 13, 2011