A fairly amazing animated video from CSIRO which illustrates how amyloid plaques accumulate in the brain. There seems to be some disagreement as to the role of plaque in the development of Alzheimer’s, but there is no question that there is a connection.
It can be difficult to visualize the plaques that Alois Alzheimer first described over one hundred years ago. It is even more difficult to understand how these proteins form. Some of our best neuroloscientists are working frantically to understand why.
I want to recognize and thank Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia’s national science agency, for making this enlightening video available. I hope they don’t mind that I am eager to share it. I also re-printed the transcript below so you would have any necessary citations and links.
Alzheimer’s Enigma – The Video
[Screen shows CSIRO logo with picture of cells inside the brain and the words Alzheimer’s Enigma]
Alzheimer’s disease is a major unsolved puzzle in medical research.
[Words disappear off screen and image shows close up of brain cells]
Currently there is no cure, no effective treatment, not even certainty about its cause.
[Image changes to show a human brain]
As Alzheimer’s disease progresses brain tissue shrinks and dies.
[Image shows brain tissue shrinking and dying]
This causes a gradual loss of short term memory, difficulties thinking, confusion and behavioural changes, ultimately leading to death.
[Words appear on screen next to brain – Memory Loss, Difficulty Thinking, Confusion, Unusual Behaviour. Image then changes to show picture of brain cells]
An early sign of the disease is the build-up of plaques around the cells in the brain.
[Image shows plaques appearing on cells in the brain]
For decades it was unclear what these plaques were made of. We now know they are made from one of your body’s own proteins.
[Image shows close up of proteins in the brain]
Plaques develop from this protein called APP which occurs on the molecular surface of brain cells. Like all proteins APP has a use by date. It needs to be broken down and recycled to keep your cells healthy.
To understand how APP is recycled and forms plaques we need to look inside the cell.
[Image shows inside of a brain cell]
Here we see other proteins assembling on the inner surface of the cell creating a lattice.
[Image shows different proteins assembling and overlapping on surface of a cell]
This structure plucks away a piece of the membrane forming a package called a vesical which contains APP proteins.
[Image shows picture of a vesicle]
The lattice disassembles allowing the vesicle to transport APP to other parts of the cell.
[Image shows proteins detaching and floating away]
The parts of the APP that were on the outside of the cell are now on the inside of the vesical.
[Image shows original proteins on inside of vesicle]
Vesicles are constantly transporting proteins back and forth between different parts of the cell.
[Image shows vesicles floating in and out of a cell]
This continuous transport is needed so that old or damaged proteins can be broken down and recycled into fresh new proteins keeping the cells healthy and functional.
[Image changes to close up of proteins]
The first step in this break down is done by an enzyme that cuts the part of APP that was previously outside the cell.
[Image shows enzyme attaching to a protein and protein detaching]
This leaves a stub of APP embedded in the membrane.
[Image shows proteins detaching and floating away]
A second enzyme cuts the remaining stub leaving smaller fragments that are then released from the membrane.
[Image shows stubs detaching and floating away]
Normally these fragments are further broken down but during Alzheimer’s disease one of the fragments escapes recycling and instead accumulates outside the cell.
[Image shows fragments joining together]
At higher concentrations these fragments begin sticking together to form long fibres. The fibres clump together in masses called plaques.
[Image shows plaques attached to brain cells]
The build-up of plaques in the brain can take place over several decades and is one of the main indications of Alzheimer’s disease.
[Image shows human brain changing colour. Image changes to show a healthy human brain next to an Alzheimer’s affected brain]
Plaques can occur years before any loss in brain function is seen.
[Images shows blood cells moving along a tunnel]
Recently scientists have identified changes in blood proteins that also occur years before the onset of Alzheimer’s.
[Image shows scientist holding test tube of blood]
This work has led to new blood tests that can easily and accurately diagnose Alzheimer’s disease before symptoms occur.
[Image shows scientist placing test tube in rack with others]
These new diagnostic tests together with other rapid advances in the life sciences mean we are closer than ever to solving the century long enigma of Alzheimer’s disease.
[Music plays while credits appear on screen: Animation and Narration Chris Hammang. Scientific Consultation Dr William Wilson, Dr Oliver Salvado. Sound Design and Recording Thom Kellar. Artistic Direction Christian Stolte, Drew Berry. Producers Dr Seán O’Donoghue, Dr Kate Patterson. Imaging Data Dr Pierrick Bourgeat]
[New text appears alongside sponsor logos: Additional Thanks Kenneth Sabir, Dr Jose Varghese, Dr Julian Heinrich, Armando Faigl, Vivian Ho, David Ma, Dr Guy Barry, Prof. Colin Masters, Dr Maja Divjak]
[Music plays and CSIRO logo appears with text: Big ideas start here www.csiro.au]