A protein that stops worsening of Alzheimer’s-like disease in mice and appears to reverse the disease process has been identified, The Guardian and other news sources reported. Two newspapers quoted the Alzheimers Research Trust, which funded the study, as saying: “A drug that can stop Alzheimer’s disease from killing brain cells is the holy grail for researchers working to overcome the condition.”
Many of the reports included the fact that this study had not been conducted in humans, and that any drug that might come about as a result of the study, would not be available for several more years.
The study underlying these stories is an animal study in mice genetically engineered to have a disease like Alzheimer’s.The main aim of the study, was to identify proteins that might be used as "markers" of the Alzheimer’s disease process, and which might therefore be used to monitor disease progression, or indicate when a therapy was being effective. The newspaper reports were based on a part of this study which involved researchers looking at the effect of injecting a molecule that may have therapeutic uses on the identified "marker".
Although the results in mice were promising, we cannot yet be sure that the molecule tested will show the same results in people with Alzheimer’s or be safe for use in humans. The findings from this study are very preliminary in terms of any application to human disease.
Where did the story come from?
The study was conducted by Frank Gunn-Moore, Jun Yao, and colleagues at the University of St Andrews in Fife, Scotland, and Columbia University and the Harvey Cushing Institutes of Neuroscience in the USA. The study was funded by the Medical Research Council, Alzheimer’s Research Trust, the Cunningham Trust, USPHS, and the Alzheimer Association. It was published in the peer-reviewed journal Molecular and Cellular Neuroscience .
What kind of scientific study was this?
This was an animal study conducted in mice genetically engineered to have similar problems in their brain cells (neurons) to people with Alzheimer’s disease.
The researchers used complex methods to look at proteins from the brains of the genetically engineered mice and compared these with normal mice.They aimed to find which proteins were found at higher levels in the Alzheimer’s-like mice and to see whether they could disrupt expression of this protein.
What were the results of the study?
The researchers identified a protein called peroxiredoxin II that was expressed in higher levels in the Alzheimer’s-like mice.They also confirmed that this protein was found in higher levels in the brains of people with Alzheimer’s disease.
The researchers found that they could reduce the levels of peroxiredoxin II in mice by injecting a short protein sequence (peptide), called the ABAD decoy peptide. This prevents the process that causes brain cell death.The death of brain cells is responsible for the symptoms of Alzheimer's.
The researchers did not investigate the effects of injecting the ABAD decoy peptide on mouse memory.
What interpretations did the researchers draw from these results?
The researchers concluded that raised peroxiredoxin II levels are associated with the Alzheimer’s disease process.They also concluded that in mice with an Alzheimer’s like condition, these increases are stopped by injecting ABAD decoy protein.
What does the NHS Knowledge Service make of this study?
Although this study may be scientifically reliable, it was conducted in mice, and therefore may not be representative of what might be observed in humans.
The findings from this study are very preliminary in terms of any application to human disease.
Sir Muir Gray adds...
Better understanding of a disease is always helpful, but the delay between an animal study and the successful introduction of a drug for patients can take as long as a decade.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Daily Mail, 24 July 2007
The Daily Telegraph, 24 July 2007
The Guardian, 24 July 2007
Links to the science
Mol Cell Neurosci 2007;35:377-382.