Much of the damage done following an ischemic stroke occurs when blood flow returns: there is a sudden and overwhelming production of reactive molecules and cells die as a result. Given sufficiently potent and safe antioxidants, this harmful process could be suppressed provided a treatment is delivered rapidly:
Injectable nanoparticles that could protect an injured person from further damage due to oxidative stress have proven to be astoundingly effective in tests to study their mechanism. Combined polyethylene glycol-hydrophilic carbon clusters - known as PEG-HCCs - could quickly stem the process of overoxidation that can cause damage in the minutes and hours after an injury. The tests revealed a single nanoparticle can quickly catalyze the neutralization of thousands of damaging reactive oxygen species molecules that are overexpressed by the body's cells in response to an injury and turn the molecules into oxygen. These reactive species can damage cells and cause mutations, but PEG-HCCs appear to have an enormous capacity to turn them into less-reactive substances.
The research targeted traumatic brain injuries, after which cells release an excessive amount of the reactive oxygen species known as a superoxide into the blood. These toxic free radicals are molecules with one unpaired electron that the immune system uses to kill invading microorganisms. In small concentrations, they contribute to a cell's normal energy regulation. Generally, they are kept in check by superoxide dismutase, an enzyme that neutralizes superoxides. But even mild traumas can release enough superoxides to overwhelm the brain's natural defenses. In turn, superoxides can form such other reactive oxygen species as peroxynitrite that cause further damage.
The researchers hope an injection of PEG-HCCs as soon as possible after an injury, such as traumatic brain injury or stroke, can mitigate further brain damage by restoring normal oxygen levels to the brain's sensitive circulatory system. "This could be a useful tool for emergency responders who need to quickly stabilize an accident or heart attack victim." The study also determined PEG-HCCs remain stable, as batches up to 3 months old performed as good as new.