Neurology Central

Liposomes represent potential new method for delivering agents to the brain

A new nanontechnology developed by researchers at Penn State College of Medicine (PA,USA) may enable doctors to detect gliomas earlier than previously possible. With a median survival rate of 14 months following diagnosis, the technology could provide an opportunity to make the currently fatal cancer treatable. The study was published recently in the Journal of Neuro-Oncology.

Despite patients rarely dying due to their initial tumor, new gliomas often grow quickly and become resistant to treatment. Follow-up MRIs are given to glioma patients, however the tests rarely identify the tumors early enough to save the patient’s lives. This is due to the inability of contrast agents used to outline gliomas on the MRI to pass the blood-brain barrier (BBB) before the tumors have grown large enough to damage the barrier.

To overcome this barrier, the Penn State team lead by Xiaoli Liu and Madhan Kumar developed liposomes capable of passing through the BBB and highlighting small gliomas on an MRI. The liposomes were coupled with the contrast agent Magnevist and covered with proteins that target the receptors on glioma cells, creating a more sensitive delivery system than the traditional contrast-enhanced MRI. Both the conventional and new technology were trialled in mice.

The mechanism by which the liposomes are capable of passing through the BBB is unknown, but experiments indicate that this occurs without causing damage to the barrier, as well as without harming the animals receiving the treatment.

While recent studies have also highlighted the potential of ultrasound for enabling the movement of therapeutic agents through the BBB and into the brain, this method causes temporary disruption to the BBB which can also allow blood to enter in addition to the agent – which could have adverse side effects.

“Ultrasound, with all of its good qualities, is disruptive to the BBB, whereas we can get an agent to cross it without causing disruption,” James Connor from Penn State remarked.

The researchers hope that these liposomes will be widely used in the future to deliver both chemotherapeutic drugs and contrast agents to brain tumors in an attempt to identify and eradicate the cancer cells in one process.

Source: Penn State press release