Nature Biotechnology pp 885 - 890

Tiny cages made out of a viral protein show great promise as a way of delivering genes or drugs to the liver. The new method, described in the August issue of Nature Biotechnology, may be useful for treating various liver diseases with beneficial genes or drugs.

The cages, or nanoparticles, form spontaneously when a single protein from hepatitis B virus is produced in large quantities. Kuroda and colleagues were able to put genes or proteins inside such nanoparticles using pulses of electric current. They then injected the nanoparticles into mice that had been transplanted with small human liver tumors. The nanoparticles traveled efficiently to the human liver cells, where the genes were released and expressed at high levels.

The nanoparticles are targeted to liver cells by a short protein ‘address’ on their surface. By changing the ‘address,’ the authors could redirect the nanoparticles to a different kind of cell, suggesting that the approach could be adapted to target organs other than the liver.

Nature Biotechnology pp 891 - 896

A new approach described in the August issue of Nature Biotechnology for combating clots shows promise as a means of preventing bleeding in patients who have undergone surgery or for individuals suffering from strokes. Most treatments for dissolving clots have only a short life span in the blood circulation and can cause bleeding and serious brain injuries by indiscriminately attacking clots around the body. By attaching the anticlotting agent, tissue plasminogen activator, to the surface of red blood cells, researchers show that they can prolong the life of the clot buster in the blood and target newly forming blood clots that are most lethal to patients.

Heart attacks and strokes kill about 12 million people a year worldwide, about a million of those in the United States. But current anticlotting agents suffer several shortcomings, including short-term stability and diffusion into organs such as the brain, which often results in lethal side effects. By coating red blood cells with the tissue plasminogen activator, Vladimir Muzykantov and his colleagues tested the ability to dissolve new clots in both mouse and rat thrombosis models. Their anti-clotting agent proved more stable in circulation and avoided the problems of diffusion from blood vessels, which can cause harmful bleeding. By simply coating a patient’s red blood cells with anticlotting agent, the authors believe it should be possible to prevent many clot-related deaths that cannot be prevented using existing therapies.