OSAKA, Japan — A nasal spray that combines the benefits of two drugs may be able to treat and even prevent Alzheimer’s disease, the most common form of dementia. Researchers from Osaka City University say the potentially groundbreaking treatment combines the antibiotic rifampicin with the popular supplement resveratrol — an antioxidant found in plants.
Their study reports that experiments involving mice were so encouraging, global clinical trials are already in the planning phase. Scientists genetically engineered the animals to develop Alzheimer’s, frontotemporal dementia, or dementia with Lewy bodies — three of the main forms of the disease.
Cognitive skills in the mice dramatically improved after the team injected the chemical cocktail into their noses five times a week for four weeks. Tests after the treatment revealed that the rodents had fewer toxic proteins called amyloid beta and tau, both of which play a major role in the development of dementia onset.
Communication between neurons also improved after the spray restored synapses that connect these brain nerve cells. Researchers note that the daily dosage for each mouse was only 0.02 mg of rifampicin.
“Converted to a human dosage based on body surface area, it becomes 0.081 mg/kg/day,” explains lead investigator Professor Takami Tomiyama in a university release. “Currently, rifampicin is prescribed at 10 mg/kg/day as an antibiotic, and compared to this, we confirmed an effect at a much lower dosage.”
Resveratrol prevents side-effects in the liver
Previous studies by the team found that rifampicin could remove amyloid beta and tau from the brains of mice. However, the drug also has a link to side-effects, including liver damage. Luckily, resveratrol boosts the functioning of the organ. It’s a naturally occurring ingredient in wine, fruit, nuts, and chocolate — and manufacturers sell it as a food supplement.
“To combat the negative side effects of the existing drug rifampicin, we thought of combining it with the hepatoprotective effects of resveratrol,” Prof. Tomiyama says.
After adding this antioxidant to the mix, researchers found levels of liver enzymes in the blood — a marker of damage that normally increases with rifampicin — remained normal. Additionally, a chemical called BDNF (brain-derived neurotrophic factor) which is vital for learning increased in the brain’s memory center — the hippocampus.
It’s a benefit that study authors did not see when administering rifampicin by itself. Prof. Tomiyama adds that the results indicate this fixed-dose combination is better than previous treatments in terms of both its safety and effectiveness.
Finding a cure for the upcoming dementia crisis
The world is facing a dementia “crisis” as the population continues to grow older. Estimates show dementia cases may triple to 150 million by the year 2050.
“The number of patients with dementia has been increasing all over the world, with some sources predicting a doubling of patients every 20 years,” says first author Dr. Tomohiro Umeda. “However, there is still no effective treatment for the disease. Recent studies have shown that abnormalities begin to appear in the brains of dementia patients more than 20 years before the onset of the disease.”
The researchers used a technique known as drug repurposing to find this promising combo. With the cost of developing new treatments so high, scientists often turn to already approved medicines to see if they may also treat other conditions besides their original purpose.
Study authors note that nasal sprays would increase the drug’s transferability to the brain and further enhance the treatment’s ability to reverse dementia symptoms.
The study’s findings are published in the journal Frontiers in Neuroscience.
South West News Service writer Mark Waghorn contributed to this report.