diaDexus Release: New Study Shows That Elevated Lp-PLA2 Signals Early Endothelial Dysfunction, A Marker Of Atherosclerosis, In Humans

SOUTH SAN FRANCISCO, Calif., Jan. 18 /PRNewswire/ -- diaDexus, Inc. today announced the publication of a key study in the American Heart Association’s Journal of Arteriosclerosis, Thrombosis and Vascular Biology that demonstrates an independent, direct link between circulating levels of Lp-PLA2 and endothelial dysfunction. Endothelial dysfunction is considered a marker of early stage atherosclerosis and has been shown to significantly increase risk of cardiac and stroke events. The study completed by Amir Lerman, MD and colleagues at the Mayo College of Medicine and accompanying editorial by Carlos Iribarren, MD, PhD, Northern California Kaiser Permanente, supports for the first time the possible involvement of Lp-PLA2 in the initiation and progression of atherosclerosis in endothelial-dependent dysfunction. The authors of the study conclude “that a direct role in the initiation of endothelial dysfunction and development of early coronary artery disease would make Lp-PLA2 an ideal and novel biomarker for identifying patients at risk for future cardiac events.”

Coronary artery disease is the leading cause of morbidity and mortality in Western society. The identification of patients at risk for coronary events and those in the early stages of atherosclerosis is essential for primary prevention, but current diagnostic methods are limited in their ability to detect early atherosclerosis.

“This study is one of several that supports that Lp-PLA2 is a high value, independent predictor of cardiovascular disease,” said Richard B. Lanman, MD, Executive Vice President and Chief Medical Officer, diaDexus, Inc. “This is an important study because it begins to elucidate potential reasons for the association between Lp-PLA2 and cardiovascular events seen in a number of prospective epidemiological studies. It supports the clinical interpretation of elevated serum Lp-PLA2 signaling a greater than normal risk for heart attacks and stroke.”

Dr. Iribarren states that similar to previous reports, no correlation existed between C-reactive protein and Lp-PLA2, suggesting that the two biomarkers may be capturing non-overlapping aspects of the inflammatory response: whereas CRP is systemic acute phase reactant, Lp-PLA2 may be more specific for vascular inflammation.

Lp-PLA2 was measured using the PLAC Test, a test developed and marketed by diaDexus.

Study Details

The study involved 172 patients with no significant artery disease (< 30% stenosis). Endothelial function was assessed by the change in coronary blood flow and coronary artery diameter in response to intracoronary acetylcholine. Plasma concentrations of Lp-PLA2 were measured and divided into three groups defined by the tertiles of the Lp-PLA2. There was no significant difference among the three groups in terms of age, prevalence of hypertension and diabetes, smoking history, C-reactive protein and use of cardiac medications. The study found that patients in tertiles 2 and 3 had a significantly lower change in coronary blood flow and greater epicardial coronary artery vasoconstriction in response to acetylcholine. Patients with coronary endothelial dysfunction had significantly higher serum concentrations of Lp-PLA2 than those with normal endothelial function (246.2+/-versus 209+/-ng/mL; P=0.001). The odds ratio for coronary endothelial dysfunction in patients in the highest tertile was 3.3 (95% CI, 1.6 to 6.6).

About diaDexus

diaDexus, Inc., a privately held biotechnology company based in South San Francisco, California, is focused on the discovery, development and commercialization of novel, patent-protected diagnostic and therapeutic products with high clinical value. The PLAC(R) test, developed by diaDexus, Inc., is a blood test cleared by the U.S. Food and Drug Administration to aid in the prediction of an individual’s risk for a coronary or ischemic stroke event, in conjunction with clinical evaluation and patient risk assessment. For more information about the PLAC(R) test visit www.plactest.com. More information about the company may be found at www.diaDexus.com.

diaDexus, Inc.

CONTACT: Christina Andrian of diaDexus, Inc., +1-650-246-6476, orcandrian@diadexus.com; or Jennifer Larson of WeissComm Partners,+1-415-946-1074, or jlarson@weisscommpartners.com, for diaDexus, Inc.

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