Brain ageing under the microscope
PEOPLE'S habits – the way they live – have a decisive influence on the ageing of the brain.
These are the findings of a study called ‘Epigenetic clock explains white matter hyperintensity burden irrespective of chronological age’ by the neurovascular group at the Barcelona-based medical investigation centre, IMIM-Hospital del Mar. They note that ‘biological age’ is independent of chronological age and is ‘to a large extent dependent on our lifestyles and the appearance of brain age indicator called white matter hyperintensity burden’. This is where areas of the brain – shown by magnetic resonance imaging – appear to be ‘different’ and indicate that it is a tissue ‘that blood reaches with greater difficulty’.
Dr Jordi Jiménez-Conde, coordinator the investigation group, said: "A sizable part of the effect of the passage of time on our brain does not only come from our chronological age, that which we have on our birth certificate, but from our biological age."
The study opens the door to have new tools to improve prognosis and 'the following' of patients, with blood tests identifying which individuals have a greater tendency to have accelerated brain ageing, he said.
The investigators worked with data from 247 people who had suffered strokes. A scan allowed them to establish the level of white matter hyperintensity in their brains. And with blood tests they could work out their biological ages by analysing the level of DNA methylation of their DNA, which is modified by external factors such as lifestyle habits.
Dr Jiménez Conde said that for the first time it can be demonstrated that 'the ageing of the body has a direct association with the ageing of the brain, which is independent of the chronological age'. Biological age explains 42.7% of brain ageing measured by the presence of white matter hyperintensity, he added.
He noted that they have to continue studying the effects that genetics have on these brain lesions, which ‘could help us to better understand the biological mechanisms which participate in brain ageing’.
High levels of white matter hyperintensity are associated with having a reduced ability to recover from pathologies that affect the brain, as well as gait disturbances (walking defects), strokes and cognitive impairment. White matter hyperintensity increases with age and this is ‘not reversible’.
However, ‘action can be taken on biological age’ and the ageing of DNA can be slowed by ‘changes in our lifestyles’.
This would lead to the 'slowing down in the increase of these lesions in brain tissue and a deceleration in the ageing of the brain'. The study has been published in English at https://doi.org/10.3390/biol ogy12010033