Mammals of any age have “fatty streaks” along the walls of the vasculature, which are exactly what they sound like. (These are the slightly lighter patches in the pictures above—more obvious in the older aortas, but faintly visible in the young pair as well.) In older mammals, the fatty streaks tend to be larger, until in old age they necrotize (aka die) in the middle and turn into thick “atherosclerotic plaques” (the dark patches in the lower right picture above). These can block blood circulation, and sometimes a chunk of the plaque can break off and block circulation in smaller vessels; either of these can cause e.g. heart attack or stroke.
At any age, a lower-fat diet is associated with smaller fatty streaks and lower chance of atherosclerosis, though the streaks universally grow with age holding diet constant.
Aren’t those way less bad in rats/mice (which tend not to suffer from arteriosclerosis at the ages they manage to survive to simply b/c they die of cancer before they can develop them?)
Aren’t those way less bad in rats/mice (which tend not to suffer from arteriosclerosis at the ages they manage to survive to simply b/c they die of cancer before they can develop them?)