Written by David Mills
Scientists at a Canadian health center hope they can safely break through that protective biological wall to deliver effective drugs directly to the brain.
Researchers are focusing on an important biological wall in the human body in their search for new treatments for Alzheimer’s disease.
The scientists have started a clinical trial involving a half-dozen older adults to see if it's possible to safely pierce that protective shield known as the blood-brain barrier (BBB).
The procedure is a tricky proposition. Finding a passageway through the barrier could allow Alzheimer’s drugs to flow directly into the brain. However, opening that window can also allow germs and other harmful organisms to invade.
“The blood-brain barrier is there for good reason,” explained James Hendrix, director of global science initiatives at the Alzheimer’s Association. “You need to maintain a healthy blood-brain barrier.”
Using ultrasound to break through
The clinical trial is being conducted at the Sunnybrook Health Sciences Centre in Toronto, Canada. It involves six people between the ages of 50 and 85 who have Alzheimer’s disease. The patients will undergo two noninvasive ultrasound procedures.
In the first stage, a focused ultrasound will be applied to a small area in the right frontal lobe. In the second stage done one month later, a similar procedure will target a larger area of the same lobe. After both procedures, images will be taken of patients’ brains to see if the blood-brain barrier was safely breached.
If it’s viable, it could have an impact on Alzheimer’s treatments.
--James Hendrix, Alzheimer's Association
No drugs will be administered. Researchers say the main goal of the trial is to determine if this blood-brain barrier approach is feasible and safe.
“By opening up the [blood-brain barrier] using low frequency ultrasound, we’ve taken a small but important step that opens up a whole new vista of possibilities,” said Dr. Sandra Black, chair of neurology at the science center at the University of Toronto, in a press release. “The hope is there may be a way to eventually open up multiple little windows, in a gentle way, in order to get large molecules like drugs and even stem cells into the brain.”
“It’s an interesting approach. It’s pretty novel,” Hendrix told Healthline. “If it’s viable, it could have an impact on Alzheimer’s treatments.”
Long road still ahead
This isn’t the first time scientists at the Sunnybrook center have traveled through the blood-brain barrier. In 2015, the researchers used ultrasound techniques to pierce that biological wall to deliver chemotherapy drugs to brain tumors.
That pilot study is still ongoing. The current trial is the first time the brain barrier is being opened for Alzheimer’s treatments. But poking through the blood-brain barrier is a dicey maneuver. The barrier is there to keep bacteria, viruses, and other harmful agents from entering the brain, where they can do significant and sometimes fatal damage.
Hendrix said the delicate operation will take years to perfect, if it works at all. He said the first step will be to determine if the ultrasound procedure is safe — no small task. If it is, then the second step will be to find the proper drug that can safely slip through the barrier and effectively treat Alzheimer’s.
“The key will be to match the procedure to the appropriate drug,” Hendrix said.
Potentially a big impact
More than 5 million Americans are now living with Alzheimer’s disease. It’s the sixth leading cause of death for adults in the United States. Right now, treatments only ease the symptoms of Alzheimer’s. No treatment actually reduces the damage done by amyloid proteins, tau tangles, and other elements believed to be root causes of the disease.
So, a method that delivered effective drugs to the brain could be an important breakthrough.
“The ability to focally, temporarily, and repetitively breach the BBB to allow high concentrations of therapeutic agents to access the brain opens up a new frontier in treating a variety of brain disorders,” said Dr. Neal Kassall, chair of the Focused Ultrasound Foundation, in a statement.