One of the suspected causes of Alzheimer's disease is the accumulation of the amyloid beta (Abeta) protein in various areas of the brain. One promising way of neutralising these abnormal deposits of proteins, which are toxic to neurons, consists of "marking" them with antibodies that alert the patient's own immune system, leading it to attacking and eliminating the proteins.
Patrick Aebischer's laboratory at the EPFL (École Polytechnique Fédérale de Lausanne), in Switzerland, developed a bioactive capsule containing genetically-modified cells for producing antibodies against Abeta. The capsule is implanted in the subcutaneous tissues, and the cells produce and release a steady stream of antibodies into the blood stream, from where they spread into the brain to target the Abeta plaques.
Described as a "micro-encapsulation system", the capsule is comprised of two permeable membranes assembled by a polypropylene envelope. The device measures a total of 27mm in length, 12mm in width and is 1.2mm thick. It contains a hydrogel which promotes cell growth and can be easily reproduced for large-scale production.
For now, this system has been successfully tested on mice, which showed a significant decrease in the plaques.
This proof of concept shows that encapsulated cell implants can be used to deliver antibodies for treating Alzheimer's disease and other neurodegenerative disorders involving defective proteins.