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In recent years, coffee has moved off the “avoid” list and onto the “drink in moderation” list, as it seems to offer health benefits ranging from lower risks for multiple diseases, including type 2 diabetes, heart disease and stroke, to metabolic and anticancer. The new study, published in the journal PLOS Biology, finds that coffee may be beneficial in part because caffeine sets off a cascade of events in heart cells, starting with their energy stores, mitochondria, and ending with protection of both healthy and unhealthy hearts.
The team focused on a protein called p27, which is known among other things to influence the cell cycle. The team found that caffeine triggered the movement of p27 into the mitochondria of heart cells in mice, and in particular, the migration of the heart’s endothelial cells, which line the blood vessels. How well the endothelial cells were able to migrate, they found, relied strongly on the presence of p27, which again is bolstered by caffeine. The protein also protected heart muscle cells from dying after heart attack was induced in some of the mice. And it triggered one type of cells, fibroblasts, to differentiate into cells containing contractile fiber, essential for good heart function.
“Our results indicate a new mode of action for caffeine,” said study author Judith Haendeler, “one that promotes protection and repair of heart muscle through the action of mitochondrial p27.”
Researchers said the optimum dose for caffeine was the equivalent of about four cups of coffee per day, which other studies have suggested as well. When this amount was given to elderly mice, their cardiovascular system functioned more like younger mice. Caffeine administration also improved the heart health of pre-diabetic and obese mice.