by Darrin S. Joy and Alicia Di RadoOne of the biggest challenges to treating diseases in the brain is inside the brain itself.
Enhanced imaging lets researchers measure how permeable the blood brain barrier is. (Image courtesy of Beth Chen)
There’s a barrier between the brain and its blood supply. Normally, it protects the brain. But it also can keep medicine from getting to brain tissue.
City of Hope scientists are studying ways to sneak through this so-called “blood-brain barrier.” Bihong Beth Chen, M.D., Ph.D., clinical assistant professor in the Department of Diagnostic Radiology, and her colleagues recently made important progress. They became the first researchers to measure how changes in the barrier affect how much of a medication actually reached brain cells while cancer patients were being treated.
The work is important because it could eventually help doctors pick the most effective schedules for giving drugs to patients.
The study was part of a larger, one-of-a-kind City of Hope clinical trial. In the study, doctors treat lethal brain tumors using special stem cells that seek out cancer.
After patients had surgery to remove cancer tissue, their surgeon injected these stem cells into the brain. Four days later, the patients received an inactive chemical that speeds through the blood toward the brain, where the waiting stem cells turn that chemical into a cancer-killing drug.
To get to the stem cells, though, the substance has to jump across the blood-brain barrier. And that’s where imaging comes in.
The researchers used a type of magnetic resonance imaging, or MRI, technology to see into the brain. The MRI allowed them to watch on a screen as a special dye flowed from the blood into brain tissue. They measured how the flow changed over the next few days, and found that the blood-brain barrier was most open about five days after the procedure.
Besides giving the scientists insight into when it’s best to give patients the medicine in the study, the results give researchers a starting point for helping to guide drug timing for patients with other kinds of cancer, too.