Atherosclerosis is the clogging of arteries with fatty deposits. It is the cause of one-third of deaths worldwide due to heart disease.
There are many known risk factors, including blood cholesterol, physical inactivity, age, hypertension, obesity, and smoking.
But research has shown that in about 15% of first-time heart attacks and strokes due to atherosclerosis, none of these factors apply.
In a recent study from the University of California San Diego, researchers found that the loss of a single gene two to three million years ago in our ancestors may have resulted in an increased risk of heart disease in all humans as a species.
This could also set up a further risk for red meat-eating humans.
The study is published in PNAS. One author is Nissi Varki, MD, professor of pathology at UC San Diego School of Medicine.
Previous research has shown that naturally occurring coronary heart attacks due to atherosclerosis are non-existent in other mammals, including closely related chimpanzees.
These animals don’t develop heart attacks even they share human-like risk factors, such as high blood cholesterol, high blood pressure, and physical inactivity.
Instead, chimp “heart attacks” were due to as-yet unexplained scarring of the heart muscle.
In this study, the team reported a mutation that inactivated a gene called CMAH occurred a few million years ago in hominin ancestors.
This event may be possibly linked to a higher risk of heart attacks in humans.
Mice with this type of mutation had an almost 2-fold increase in the severity of atherosclerosis. They also had hyperactive white cells and a tendency to diabetes.
This may help explain why even vegetarian humans without any other obvious heart risk factors are still very prone to heart attacks and strokes, while other evolutionary relatives are not.
The team says that the human evolutionary loss of CMAH likely contributes to a predisposition to atherosclerosis.
This gene loss may have produced other significant changes in human physiology, including reduced human fertility and enhanced ability to run long distances.
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