Medical researchers have long sought an answer to bypassing the blood-brain barrier, a layer of tightly packed cells that surrounds each of the blood vessels of the brain.
While this barrier helps protect the vessels from toxins and infections, it also prevents doctors from effectively treating brain diseases and tumors in patients.
A team of scientists at the Sunnybrook Health Sciences Center in Canada, however, have developed a non-invasive way to circumvent the blood-brain barrier in order to deliver much-needed drugs into the brain that could better treat diseases such as Parkinson's and Alzheimer's.
The breakthrough procedure makes use of focused ultrasound and microbubbles to bypass the protective layer around the brain's blood vessels, and according to the researchers, it has already produced positive results in their clinical trials on animals.
The Sunnybrook scientists are now conducting tests in applying the new method on human patients.
Bonny Hall
One of the first patients to receive the new treatment is a woman named Bonny Hall who has been diagnosed with a type of malignant brain tumor called a glioma. Doctors often find it difficult to treat these kinds of malignancies as they tend to spread out and cannot be removed entirely through surgery.
Dr. Todd Mainprize, lead researcher of the Sunnybrook study, said that even though chemotherapy can be used to treat the remaining cancer cells following the surgical removal of the glioma, only 25 percent of the medication actually reaches the patient's brain. This explains the low survival rates of people suffering from brain cancer.
"Frankly speaking, our ability to treat this type of tumor, glioma, is not so good," Mainprize said. "Between 1940 and 2005, there has been very little progress in improving the outcome of these patients."
Brain cancer treatments have slightly improved over the past decade, but Mainprize argued that they are still not enough to properly address the issue.
Focused Ultrasound-Assisted Surgery
According to the Sunnybrook study, the new non-invasive method features three main steps.
The first part of the procedure involves giving the patient chemotherapy treatment. In Hall's case, the researchers gave her a dose of doxorubicin.
It is then followed by injecting the patient's bloodstream with harmless gas microbubbles.
For the last part, the malignant tumor is subjected to a high-intensity ultrasound beam, which causes the microbubbles to vibrate and break down the proteins found in the capillaries. This allows the chemotherapy drug to reach the tissues of the brain.
During Hall's treatment, the researchers marked the chemotherapy medications with a chemical tag to make it identifiable through magnetic resonance imaging (MRI) scans.
As the cancer drug was administered to Hall, the researchers observed how it moved through her blood vessels and into her malignant tumor.
Mainprize said the procedure went exactly as they had hoped.
Hall's tumor was extracted later in the day, and the researchers will now conduct tissue analysis on the malignancy to find out the concentration of the cancer drug that was able to penetrate it.
Nine other patients diagnosed with brain cancer will also undergo the same procedure, after which the researchers said they will publish the results of their study in full.
Photo: Allan Ajifo | Flickr
