Top Santé: Where is the research on Alzheimer’s disease?
Dr Hervé Chneiweiss One of the most interesting areas concerns the links between chronic inflammation and disease. This new lead could involve the microbiota, that is to say the bacteria of our digestive system. There is an ongoing dialogue between the intestinal floraand the central nervous system. It can promote, in the brain, an inflammatory phenomenon, itself known today as being a marker of Alzheimer’s disease.
TS Could we really prevent the disease by modifying the intestinal flora?
Dr. HC Many studies focus on this. How the microbiota can be responsible for brain inflammation is poorly understood. It is likely that, in a few years, we will be able to give really serious dietary advice to rebalance the microbiota and thus contribute to delaying the onset of Alzheimer’s diseasefailing to avoid it.
TS Does taking anti-inflammatories have any interest?
Dr HC Clinical trials with non-steroidal anti-inflammatories (therefore excluding cortisone) have not shown any benefits. The inflammatory mechanisms present in the Alzheimer’s disease are not the same as those of the peripheral inflammations observed in the rest of the organism. We need to better target the mechanisms at work in the brain. The cells involved are microglial cells (constituting microglia), which play a role in immunity. They have long been neglected, because we were mainly interested in the “noble” cells of the brain, the neurons. Currently, microglia fascinates researchers.
TS Are we making progress in diagnosis?
Dr. HC For a long time, this diagnosis was based solely on the symptoms of dementia, which may have other causes. It could only be confirmed post mortem, by brain analysis. And, in 50% of cases, we found that it was wrong! Thanks to advances in imaging and our knowledge of microglial cells, it is now 95% certain. We can even predict the development of the disease in families at risk. Positron emission brain imaging (Pet Scan) shows that these cells can be in an “activated” (inflammatory) state ten to twenty years before the first symptoms!
TS Where is the hoped-for vaccine?
Dr HC In Alzheimer’s disease, certain proteins (amyloid and tau) clump together. The formation of these aggregates is associated with the degeneration of neurons. It therefore seems logical to want to prevent it either by vaccination or by directly injecting antibodies against the aggregates. Tests have taken place, they are disappointing. Does this mean that this track is bad? No. Research continues to understand why the aggregates appear. Are they responsible for neuronal death? Or are they just a sign of disease? The question is not cleared up. But it is likely that in the next ten years we will have drugs that act before the formation of the aggregates.
TS What are you working on in your lab?
Dr HC Laure Rondi-Reig is interested in the phenomenon of spatial disorientation that affects patients. Patients lose their ability to navigate in space: when they go out, they get lost and are found wandering far from their homes. Laure works both on mouse models and on imaging (functional MRI) in humans. She was able to show the crucial role of the cerebellum (rear part of the brain) in these disorientation phenomena and explore some molecular mechanisms that could limit these symptoms.
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