Heart attack and stroke are the first and second leading cause of death in developed countries, respectively. Since the disease often leads to sudden death with few specific prognostic symptoms, early diagnosis is very important. For this purpose, imaging techniques such as magnetic resonance imaging (MRI) are widely used to identify narrowing or obstruction of blood vessels.
In MRI, interface agents improve the visibility of structures such as smaller blood vessels within the body. Just as satellites or global positioning systems (GPS) provide traffic congestion information, the MRI interface agents can provide accurate information about vascular conditions such as vascular obstruction and stenosis. Common products are the gadolinium-based interface agents. Free gadolinium ions have a high toxicity, so they must be given in chelated forms. However, even then there are some health risks in nephrogenic systemic fibrosis for patients with poor renal function. Attempts have been made to use iron-based paramagnetic nanoparticles as different agents, but their renal cleansing profile needs to be improved to prevent undesirable accumulation in the liver and other organs.
Develop a collaborative research team led by Professor CHEON Jinwoo, director of the Center for Nanomedicine (CNM), Institute of Basic Science (IBS) at Yonsei University, Seoul, South Korea and CHOI Professor Byoung Wook from Yonsei University College of Medicine -performance MRI interface for 3D vascular mapping. The researchers developed a nanoparticle-based MRI interface agent, called SAIO (Supramolecular Amorphous similar to Iron Oxide). It is 5 nanometers in size, which is about 1,500 times smaller than the microbiological diameter. This allows blood to circulate over blood vessels in the body.
The SAIO is a special nanoparticle composed of a polysaccharide core composed mainly of dextran cross-linked with other molecules. This core is then coated with an iron oxide surface to give it paramagnetic properties at room temperature. The hybrid nature of SAIOs provides them with both excellent bioavailability and image performance. The researchers compared the interface performance, retention, and renal cleansing profile of the SAIO against Dotarem (gadolinium-based agent) and iron oxide nanoparticles.
SAIO is one of the highest resolution image representatives, which is 10 times more accurate than the image created using different comparison representatives. It has achieved 3D brain tissue mapping that clearly identifies brain microvessels as thin as hair (100 microns) in animal experiments. In addition, with excellent resolution, the elevation lasts much longer (> 10 min) compared to Dotarem (<2 min), which gives the radiologist sufficient time to perform the imaging procedures. These excellent properties of SAIO allowed the researchers to visualize the heart blood vessels, which are only visible by conventional MRI interface agents.
In addition to obtaining a high solubility, inhibition of the different agent through urine is particularly important to prevent it from accumulating inside the body, which can cause a number of side effects. SAIO has a good renal cleansing profile without accumulation in liver or spleen. SAIO was also found to be stable without accumulation or smelting iron for up to a year.
Director of Cheon said, “SAIO is a next generation interface agent that satisfies both ambition and safety at the same time” and Professor Choi said, “SAIO is expected to play a vital role in increasing the accuracy of diagnosis of cerebro-cardiovascular diseases such as stroke, myocardial infarction, angina, and depression. “
Source:
Institute for Basic Science
Magazine Reference:
Shin, TH., et al. (2021) T1 high-resolution MRI through dextran nanoparticles that are easily cleaned with an iron oxide shell. Nature Biomedical Engineering. doi.org/10.1038/s41551-021-00687-z.