Alzheimer's drugs might get into the brain faster with new ultrasound tool, study shows

Scientists have discovered a method to expedite the absorption of Alzheimer's drugs into the brain by briefly disrupting its safeguarding barrier. Although the novel experiment was conducted on only three patients, the method facilitated the removal of Alzheimer's distinctive, brain obstructive plaque in targeted regions, reported scientists on Wednesday. Dr. Ali Rezai from West Virginia University's Rockefeller Neuroscience Institute, who led the research, hopes to expedite the effects of new Alzheimer's medicine that typically takes time to show results.

The primary challenge lies in the blood-brain barrier, a biological shield within blood vessels that prevents harmful substances from permeating the brain via bloodstream. While acting in defense, this barrier also obstructs medication for Alzheimer's, tumors, and other neurological conditions from reaching targeted areas in the brain. For sufficient drug delivery, it necessitates escalating dosage for prolonged periods.

Presently, scientists are employing a technique named focused ultrasound to create temporary openings in this barrier. This involves injecting minute bubbles into the bloodstream, which are later targeted with soundwaves from a helmet-like device. The resultant energy waves cause the bubbles to vibrate, leading to loosening of gaps in the protective lining, permitting medication to percolate. Preliminary studies show that safe tiny openings can be created this way, which usually close in about 48 hours.

Rezai's team has advanced this method by simultaneously administering an Alzheimer's medication. Many promising Alzheimer's drugs, currently available or under development, aim to marginally slow the progression of the disease. These drugs are intended to eradicate a sticky protein known as beta amyloid, which accumulates in certain brain areas and hence require periodical intravenous infusions for nearly 18 months.

The proof-of-concept study involved applying focused ultrasound after each intravenous dose of Aduhelm, a known Alzheimer's medication, to a specific part of the brain where the amyloid proteins are prevalent. This allowed the blood-brain barrier to momentarily open and allow more of the medication to infiltrate the targeted area.

Pre and post-treatment PET scans revealed an approximate 32 per cent surge in plaque reduction in areas where the blood-brain barrier was disrupted compared to the same region on the other side of the brain. Observing these results, Dr. Eliezer Masliah from the National Institute on Aging described them as compelling and exciting, paving the way for broader, more extensive research. However, he alerted the need to evaluate whether quicker plaque removal could potentially escalate the risk of a rare but serious side effect - swelling and bleeding in the brain.

Despite Alzheimer's being the primary focus, researchers are studying the feasibility of this technique on breaching the blood-brain barrier for supplying more chemotherapy for cerebral tumors and curing other conditions. Further testing on more advanced drugs, such as Leqembi, is also on the horizon, but larger studies will be needed to assess whether combining focused ultrasound with Alzheimer's drugs visibly benefits patients.