Discovery could explain failed clinical trials for Alzheimer's, and provide a solution

Researchers at King's College London have discovered a vicious feedback loop underlying brain degeneration in Alzheimer's disease which may explain why so many drug trials have failed. The study also identifies a clinically approved drug which breaks the vicious cycle and protects against memory-loss in animal models of Alzheimer's.

Overproduction of the protein beta-amyloid is strongly linked to development of Alzheimer's disease but many drugs targeting beta-amyloid have failed in clinical trials. Beta-amyloid attacks and destroys synapses - the connections between nerve cells in the brain - resulting in memory problems, dementia and ultimately death.

In the new study, published in Translational Psychiatry, researchers found that when beta-amyloid destroys a synapse, the nerve cells make more beta-amyloid driving yet more synapses to be destroyed.

"We show that a vicious positive feedback loop exists in which beta-amyloid drives its own production," says senior author Dr Richard Killick from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN). "We think that once this feedback loop gets out of control it is too late for drugs which target beta-amyloid to be effective, and this could explain why so many Alzheimer's drug trials have failed."

"Our work uncovers the intimate link between synapse loss and beta-amyloid in the earliest stages of Alzheimer's disease," says lead author Dr Christina Elliott from the IoPPN. "This is a major step forward in our understanding of the disease and highlights the importance of early therapeutic intervention."

The researchers also found that a protein called Dkk1, which potently stimulates production of beta-amyloid, is central to the positive feedback loop. Previous research by Dr Killick and colleagues identified Dkk1 as a central player in Alzheimer's, and while Dkk1 is barely detectable in the brains of young adults its production increases as we age.

Instead of targeting beta-amyloid itself, the researchers believe targeting Dkk1 could be a better way to halt the progress of Alzheimer's disease by disrupting the vicious cycle of beta-amyloid production and synapse loss.

"Importantly, our work has shown that we may already be in a position to block the feedback loop with a drug called fasudil which is already used in Japan and China for stroke." says Dr Killick. "We have convincingly shown that fasudil can protect synapses and memory in animal models of Alzheimer's, and at the same time reduces the amount of beta-amyloid in the brain."

The researchers found that in mice engineered to develop large deposits of beta-amyloid in their brains as they age, just two weeks of treatment with fasudil dramatically reduced the beta-amyloid deposits.

Researchers at King's College London are now seeking funding to run a trial in early stage sufferers of Alzheimer's to determine if fasudil improves brain health and prevents cognitive decline.

Professor Dag Aarsland from the IoPPN said "As well as being a safe drug, fasudil appears to enter the brain in sufficient quantity to potentially be an effective treatment against beta-amyloid. We now need to move this forward to a clinical trial in people with early stage Alzheimer's disease as soon as possible."

Christina Elliott, Ana I Rojo, Elena Ribe, Martin Broadstock, Weiming Xia, Peter Morin, Mikhail Semenov, George Baillie, Antonio Cuadrado, Raya Al-Shawi, Clive G Ballard, Paul Simons, Richard Killick.
A role for APP in Wnt signalling links synapse loss with β-amyloid production.
Translational Psychiatryvolume 8, Article number: 179 (2018). doc: 10.1038/s41398-018-0231-6.

Most Popular Now

Preventing tumor metastasis

Researchers at the Paul Scherrer Institute, together with colleagues from the pharmaceutical company F. Hoffmann-La Roche AG, have taken an important step towards the dev...

A new drug could revolutionize the treatment of ne…

The international team of scientists from Gero Discovery LLC, the Institute of Biomedical Research of Salamanca, and Nanosyn, Inc. has found a potential drug that may pre...

Interactions discovered in cells insulating nerve …

Schwann cells form a protective sheath around nerve fibres and ensure that nerve impulses are transmitted rapidly. If these cells are missing or damaged, severe neurologi...

Breast cancer can form 'sleeper cells' after drug …

Breast cancer medicines may force some cancer cells into 'sleeper mode', allowing them to potentially come back to life years after initial treatment. These are the early...

Anniversary of the pivotal RE-LY® trial marks a de…

Boehringer Ingelheim today announces the ten-year anniversary of the RE-LY® trial publication(1-3) recognising the contribution made in the decade since by patients, heal...

Experimental validation confirms the ability of ar…

Insilico Medicine, a global leader in artificial intelligence for drug discovery, announced the publication of a paper titled, "Deep learning enables rapid identification...

AstraZeneca agrees to buy US FDA Priority Review V…

AstraZeneca announced that it has agreed to buy a US Food and Drug Administration (FDA) Priority Review Voucher (PRV) for a total cash consideration of $95m from a subsid...

Boehringer Ingelheim eExpands KRAS cancer program …

Boehringer Ingelheim and Lupin Limited (Lupin) announced a licensing, development and commercialization agreement for Lupin's MEK inhibitor compound (LNP3794) as a potent...

Pfizer invests half billion dollars to advance sta…

Pfizer announced an additional half billion dollar investment for the construction of its state-of-the-art gene therapy manufacturing facility in Sanford, North Carolina...

FDA grants Fast Track designation for Farxiga in c…

AstraZeneca today announced that the US Food and Drug Administration (FDA) has granted Fast Track designation for the development of Farxiga (dapagliflozin) to delay the ...

The Pfizer Foundation invests in 20 organizations …

The Pfizer Foundation announced 20 grants* to help non-governmental organizations (NGOs), non-profits and social enterprises address critical health challenges related to...

Tagrisso approved in China as a 1st-line treatment…

AstraZeneca today announced that it has received marketing authorisation from China's National Medical Products Administration (NMPA) for Tagrisso (osimertinib) as a 1st-...