Spontaneous experimental atherosclerosis in hypercholesterolemic mice advances with ageing and correlates with mitochondrial reactive oxygen species.

Ageing and atherosclerosis are associated with oxidative stress. Mitochondrial redox function declines with ageing. Here we tested whether ageing LDL receptor knockout mice (LDLr-/-) develop spontaneous atherosclerosis and whether mitochondrial reactive oxygen species (mtROS) correlate with atherosclerosis. Compared with young mice, aged LDLr-/- mice exhibited 20-fold larger aortic lesion size, although the plasma cholesterol levels did not vary between age groups. The lesion sizes increased exponentially from 3 to 24months of age (r=0.92, p=0.0001) and were correlated with mtROS across the age range (r=0.81, p=0.0001). Thus, LDLr-/- mice develop spontaneous diet-independent atherosclerosis, that advances exponentially with ageing. We propose that age related increases in mtROS contribute to accelerate atherosclerosis development in hypercholesterolemic mice.