Exercise frequency affects morphology of aortic calcium deposits in female hyperlipidemic mice as determined by 18F-NaF PET.

While exercise is known to benefit cardiovascular health, the optimum regimen, in terms of both speed and frequency, remains unclear, especially for those with existing calcific atherosclerosis. We previously found that, in atherosclerotic female mice, lower speed, but not higher speed, treadmill running had a beneficial effect on the morphology of aortic calcium mineral deposits, as determined by 18F-NaF PET imaging, where 18F-NaF tracer uptake reflects mineral surface area, which, in turn, reflects risk. To determine optimal exercise frequency at the lower speed, 18F-NaF tracer uptake and histochemical analysis of alkaline phosphatase, calcium mineral, and CD68 in the aortas of aged Apoe-/- mice exercising 0, 3, or 5 days/week were performed. Images were acquired at baseline and at the end of the study. Although by histochemistry, all 3 groups had similar levels of osteoblastic differentiation and similar numbers of aortic calcium deposits, 18F-NaF tracer uptake increased significantly over the study duration in the 0- and 3-days/week. groups but not in the 5-days/week. group. Calcification also had a significant negative correlation with macrophage infiltration in the 5-days/week. group. In summary, the findings suggest that greater frequency running regimens alter aortic calcification in ways that may provide better cardiovascular benefits.