In a breakthrough Alzheimer’s treatment, scientists from the
Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland have developed
an implantable capsule that works by turning the patient's immune system
against the disease. The lab of Patrick Aebischer at EPFL developed this
bioactive capsule which contains cells that have been genetically engineered to
produce antibodies against amyloid-β.
When German psychiatrist and pathologist Alois Alzheimer described
Alzheimer’s disease for the first time in 1906, he brought to light the
presence of two types of lesions in the brain – Senile plaques and Neurofibrillary
tangles. Senile plaques are caused by over-accumulation of the protein Amyloid
beta (amyloid-β) in different parts of the brain.
The capsule, when implanted under the skin, releases
antibodies that travel to the brain and activate the patient's immune system to
clear beta-amyloid protein.
Scientists have long been looking for ways to tackle these
plaques, and they discovered one of the most promising ways to fight it is to
“tag” the beta-amyloid proteins with antibodies that signal the immune system
to attack and destroy them, before they can form plaques.
In the latest study, Mr. Aebischer of the Brain Mind
Institute at EPFL and colleagues note that such a treatment needs to be
administered in the early stages of memory loss in order to be most effective.
The procedure requires repeat injections, which could have adverse effects.
They say their new implantable capsule could offer a safer
and highly effectual alternative.
The capsule, described as a "macroencapsulation
device," is made of two permeable membranes sealed together with a
polypropylene frame. The device is 27 mm in length, 12 mm wide and 1.2 mm
thick. It comprises cells taken from genetically engineered muscle tissue that
can produce high levels of antibodies that are able to recognize and target
beta-amyloid proteins in the brain.
The cells inside the capsule are made not only to be able to
produce antibodies, but also to be compatible with patient, in order to not
trigger the immune system against them, like a transplant can. This is where
the capsule’s membranes come into play. The permeable membranes of the capsules
allow the cells to soak up all the nutrients and molecules they need from
surrounding tissue.
When the capsule is implantedin tissue under the skin, it gradually releases the antibodies into the
bloodstream. The antibodies then travel from blood to the brain to track down
and tag beta-amyloid
The device was successfully tested on mice which showed
great success. The mice used were a genetic line of mice that is commonly used
to replicate Alzheimer’s disease. The test showed substantial reduction of
amyloid-β plaque load.
Verily, over a period of 39 weeks, the capsules produced a
constant flow of antibodies, which prevented the formation of amyloid-β plaques
in the brain. The treatment also decreased the amount of phosphorylation of the
protein tau seen in mice. Tau protein is also believed to play a role in
Alzheimer's development by forming "tangles" – another hallmark of
the disease.
The proof-of-concept study has been hailed as a landmark. The
researchers say it clearly demonstrated that implantable capsules can be used
safely and successfully to deliver antibodies in treating Alzheimer’s and other
neurodegenerative diseases that feature defective proteins.
