Brain scans link signs of cellular aging to symptoms of Alzheimer’s

According to a new study led by Anya Topiwala of Oxford Population Health, a division of the University of Oxford in the United Kingdom, and published on March 22^nd, 2023 in the open-access journal PLOS ONE, changes in the brain caused by Alzheimer’s disease are connected to telomeres shortening, the protective caps on the ends of chromosomes that shorten as cells age.

On chromosomes, telomeres prevent DNA deterioration, but they get shorter every time a cell divides. Short telomeres are markers of cellular aging and stress, and it is also linked to a higher risk of neurological and mental disorders.

The relationship between telomere length and the alterations that take place in the brains of patients with neurological disorders is currently poorly understood. Understanding those connections could shed light on the biological mechanisms behind neurodegenerative diseases.

The UK Biobank is a substantial biomedical database and research resource that contains anonymized genetic, lifestyle, and health information on half a million UK participants.

In the new study, researchers compared telomere length in white blood cells to findings from brain MRIs and electronic health records from more than 31,000 participants. According to the study, those with longer telomeres also frequently had better brain health.

They possessed larger hippocampi and larger volumes of grey matter in their brains, both of which are shrunk in Alzheimer’s patients. The outer, folded layer of grey matter in the brain known as the cerebral cortex, which thins as Alzheimer’s disease advances, was also linked to longer telomeres.

. Longer telomeres could therefore help protect people from developing dementia, albeit there was no relationship with stroke or Parkinson’s disease, according to the researchers.

Overall, the results suggest that shorter telomeres could be related to several changes in the brain related to dementia. This investigation into the relationships between telomere length and brain MRI markers is the largest and most comprehensive one to date.

The correlations imply that neurodegenerative diseases could have a biological route resulting from accelerated aging of the brain, as shown by telomere length.

The study authors concluded, “Overall, the results suggest that shorter telomeres could be related to several changes in the brain related to dementia. This investigation into the relationships between telomere length and brain MRI markers is the largest and most comprehensive one to date. The correlations imply that neurodegenerative diseases could have a biological route resulting from accelerated aging of the brain, as shown by telomere length.”