The spinal fluid analysis also points to possible new avenues of therapy. The 3-year study found significant differences in fatty acids in cerebrospinal fluid -- the fluid that bathes the brain and spinal cord -- between Alzheimer's and cognitively healthy patients. In particular, Omega-3 fatty acid levels were found to be considerably reduced in Alzheimer's patients.
"We measured a vast number of lipid compounds in the cerebrospinal fluid and found a lot of changes, especially in Omega-3 fatty acids and also in the mono-unsaturated fatty acids," said Dr. Alfred Fonteh, HMRI Senior Biochemist, and the lead researcher on the study. "These (Omega-3's) are the kind of fatty acids that you often find in a Mediterranean diet."
Dr. Fonteh noted that in earlier studies people in countries with high-fish diets -- foods particularly rich in Omega-3 fatty acids -- were found to have better memory function and tend not to have as high an incidence of Alzheimer's disease. These data formed part of the hypothesis that led to his study. In addition, it was known from earlier studies of Alzheimer's disease that the brain -- which contains abundant fatty acids -- shrinks considerably in Alzheimer's patients.
This was the first study of its kind to be conducted on live human subjects. "For a long time people have done animal studies that found that if you provide a certain amount of Omega-3 fatty acids to rats, it prevents memory loss," Dr. Fonteh continued. "But no one has ever studied humans to discover levels of Omega-3 fatty acids in the brain, or whether they're actually depleted or have any significance in disease." By looking in cerebrospinal fluid, the researchers have a more direct read-out of changes in the brain, rather than looking in blood where molecular changes originating from the brain are mixed together with changes from all the other organs.
The findings of the study raise new questions, to explore new treatment options. The changes in fatty acids within cerebrospinal fluid could be used as markers to characterize the stage of Alzheimer's disease and perhaps to monitor response to therapies. Intriguingly, looking at restoration of fatty acids may be an approach to therapy, and the HMRI group will be addressing the results of this study with further research in the same patients, new study participants, in parallel with laboratory studies.