RE: Minor brain spark18 Feb 2022 16:11
Hi Thoth - a couple of articles from this week's New Scientist for you. First is on Alzheimer's, second is on aging. I read an article a short while ago noting that even by repairing telomeres we'd still have an upper age limit of around 120. Not sure I'd want a world of old duffers using up the world's resources!
The immune system may remove brain protein plaques associated with Alzheimer’s disease on a circadian schedule and this could be affected by sleep loss, suggests a study using mouse cells.
The circadian schedule is an internal clock that controls sleep and a vast array of other bodily processes on a roughly 24-hour cycle. Doctors have long observed that people with Alzheimer’s disease have sleep disturbances and circadian disruption, but it remains unclear the extent to which this disruption could be a cause for the condition itself.
Now, Jennifer Hurley at the Rensselaer Polytechnic Institute in New York and her team have found one possible mechanism by which beta-amyloid plaques, which are found in high numbers in the brains of people with Alzheimer’s, could be related to sleep. They think the plaques are cleared away by macrophages, immune cells that destroy foreign material, according to the body’s daily rhythms.
To investigate this, the team extracted macrophages from mice bone marrow and fed them beta-amyloid plaques at different times of day. By counting the plaques the cells had consumed, the researchers could map out the circadian rhythms of the macrophages.
Hurley and her team also identified a class of circadian-controlled proteins involved, called heparan sulphates, which Hurley thinks may signal to the macrophages when to clear away the plaques (PLoS Genetics, doi.org/hgkd).
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Permanently adopting a healthier diet in place of typical Western fare may extend life by a decade or more on average for people under 60.
“The estimated life extension is mainly due to a reduction in the risk of heart disease, diabetes and cancer,” says Lars Fadnes at the University of Bergen in Norway.
His team started with recent meta-analyses of the effect of eating various amounts of particular food types, such as fruits. These findings were combined with data on global mortality and what people currently eat to estimate the impact of a permanent change in diet.
The highest estimates of lifespan extension are based on a diet designed to maximise the health benefits. This involves having no red or processed meat, no sugar-sweetened beverages, less dairy and eggs, and eating more legumes, whole grains and nuts.
For younger adults, the benefits would be greatest. A 20-year-old man who moved to the optimised diet would live 13 years longer on average. For a woman, the equivalent figure is 11 years (PLoS Medicine, doi.org/hgjp).
Eighty-year-olds of either sex would reap the smallest benefits, living about three years longer.
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