Posted in | Nanomedicine

Visualizing Vulnerable Plaques that Can Cause Heart Attack using NanoScan's Novel Contrast Agent

NanoScan Imaging, LLC, a developer of radio-opaque contrast agents for use with computed tomography (CT) to aid in the diagnosis of cardiovascular disease and cancer, today announced the publication of new data demonstrating the use of its investigational, radio-opaque contrast agent (N1177) to visualize vulnerable plaques that can cause heart attack or stroke using advanced, non-invasive and high-resolution computed tomography (CT) techniques. Results of the study were published in the current issue of the peer-reviewed Journal of Nuclear Medicine (J Nucl Med. 2009 Jun;50(6):959-965).

N1177, an emulsified suspension that is composed of crystalline iodinated particles dispersed with surfactant, is being developed to visualize blood vessels and organs of the body, with particular interest in the arteries, veins and the heart chambers using a technique known as CT angiography (CTA). N1177 also accumulates in macrophage cells allowing for their detection with CT.

Macrophages are the predominant cells involved in creating the progressive plaque lesions of atherosclerosis, a progressive disease and the main cause of cardiovascular disease - the number one killer worldwide. Atherosclerosis is caused by the build-up of plaques (fatty or fibrous deposits) in the artery walls. This can result in the narrowing of the arteries, which can reduce the supply of blood to vital organs such as the heart and brain. Plaques can also rupture, leading to a sudden, complete blockage of blood flow. Plaques that are at high-risk or “vulnerable” to rupture are characterized by strong macrophage infiltration, which result in acute plaque destabilization and thrombus formation.

“Plaques with strong macrophage infiltration are believed by medical experts to be at higher risk of rupture, which can lead to sudden cardiovascular events, such as heart attack or stroke, often without any prior symptoms," said Don Skerrett, Chief Executive Officer of NanoScan Imaging. “The ability to examine and visualize vulnerable plaques in the arteries by obtaining detailed pictures using CT imaging may be of value to drug developers seeking to examine changes in the size of plaque in response to therapeutic intervention, such as the use of cholesterol lowering statins. Ultimately, we believe that N1177 may help physicians identify high-risk but asymptomatic patients in new ways to treat a heart attack before it occurs.”

In the study, researchers from the Mount Sinai School of Medicine investigated whether or not N1177 correlated with macrophage activity evaluated with 18Fluorine-fluorodeoxyglucose (FDG) on Positron Emission Tomography (PET)/CT and also macrophage density on histology. After only two hours, the enhancement of the macrophage rich plaque after the injection of N1177 was significantly higher and specific inside of the vessel wall in rabbits fed a high cholesterol diet compared to control rabbits fed a normal chow diet (p < 0.05). In addition, the intensity of enhancement in the aortic wall measured with CT after injection of N1177 correlated with both FDG uptake on PET/CT (p<0.001) and macrophage density on immunohistology (p<0.001). The results suggest a role for N1177 in non-invasive identification of high-risk atherosclerotic plaques with CT.

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