While preparing trials against Alzheimer's disease, researchers discovered that their molecule already existed naturally in human blood.
The story begins with a small molecule called HAEE, made in the laboratory. It consists of four basic building blocks of proteins, known as amino acids. The researchers designed it to prevent certain proteins from clumping together in the brain, a phenomenon associated with Alzheimer's disease.
A molecule developed to combat Alzheimer's already existed in our blood
These proteins, called amyloids, can accumulate between nerve cells and form plaques. The HAEE molecule was designed to interfere with the action of zinc, which facilitates their aggregation. Experiments on animals had produced encouraging results, but its effectiveness as a treatment in humans has not been demonstrated.
Before clinical trials could be considered, the team had to develop a method to find HAEE in the blood and track what happens to it. It was during these checks that a surprise emerged: the compound was already present in the samples, even in people who had never received it.
The researchers analyzed the blood of 150 volunteers without a diagnosed cognitive disorder. All naturally possessed this same small molecule. This means that the human body produces, or contains through a mechanism yet to be clarified, a compound identical to the one designed in the laboratory.
The team then studied 200 people who had received a clinical diagnosis of Alzheimer's disease. The average concentration of HAEE in their blood was about 175 picograms per milliliter, compared with 360 in the control group, or almost half as much. This difference was clear, but it does not yet explain why it exists.
Does a lack of HAEE promote the disease, or does the disease lower its level? The researchers do not have the answer. The analyses were conducted in patients who had already been diagnosed. They therefore do not prove that the molecule could detect Alzheimer's before symptoms appear.
The results should also be interpreted cautiously. The diagnoses were not systematically confirmed by biological examinations of the brain. The study was funded by the company that holds patents concerning the use of HAEE. These factors make verification by other teams necessary.
This discovery could open up two new avenues: better understanding the natural role of HAEE and determining whether its amount in the blood can provide useful information about Alzheimer's. But at this stage, there is neither a validated blood test based solely on this molecule nor a HAEE-based drug whose effectiveness in humans has been proven.