Enhanced Multi-Antioxidants Effective in Sepsis Treatment

A new study claims that synthetic ceria–zirconia (CZ) nanoparticles are effective scavengers of reactive oxygen species (ROS) free radicals, and could thus increase sepsis survival rates.

Researchers at Seoul National University Hospital (SNUH; Republic of Korea), the Institute for Basic Science (IBS; Seoul, Republic of Korea), and other institutions in Korea conducted a study to examine the use of cerium nanoparticles for treating ROS-related inflammatory diseases. By quickly converting between two oxidation states (Ce3+ and Ce4+), the cerium ion can quench typical ROS radicals such as the superoxide anion, the hydroxyl radical anion, or even hydrogen peroxide (H2O2).

To enhance the process, the researchers first synthesized 2 nm CZ nanoparticles that possess a higher Ce3+/Ce4+ ratio and faster conversion from Ce3+ to Ce4+ than those exhibited by ceria nanoparticles. The CZ nanoparticles were also coated in a hydrophilic shell of polyethylene glycol based phospholipids in order to make them soluble. The resulting nanoparticles greatly improve ROS scavenging performance, and were also found to reduce mortality and systemic inflammation in two sepsis model organisms. The study was published on July 5, 2017, in Angewandte Chemie.

“A single dose of ceria-zirconia nanoparticles successfully attenuated the vicious cycle of inflammatory responses in two sepsis models,” concluded senior author Professor Taeghwan Hyeon, PhD, of IBS, and colleagues. “The nanoparticles accumulated in organs where severe immune responses occurred, and they were successful in the eradication of reactive oxygen species, as evidenced with fluorescence microscopy and several other techniques. And importantly, the treated mice and rats had a far higher survival rate.”

ROS are chemically reactive chemical species containing oxygen, such as peroxides, superoxide, hydroxyl radical, and singlet oxygen. In a biological context, ROS are formed as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling and homeostasis. But during times of environmental stress--such as ultraviolet (UV) radiation or heat exposure--ROS levels can increase dramatically, resulting in oxidative stress and significant damage to cell structures.

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Seoul National University Hospital
Institute for Basic Science