Age-related arterial calcification in rats

In man, i) arteries calcify with age and ii) age-linked arterial calcification is amplified by vascular pathology such as hypertension or arteriosclerosis. Age-linked arterial calcification has a bad prognosis but drugs to prevent it are lacking. This is partially due to the lack of appropriate animal models. This paper looks at the extent to which arteries calcify with age in the rat and whether hypertension or arteriosclerosis amplifies such calcification. Total calcium levels were determined by acid digestion and flame spectrophotometry and intracellular calcium levels ([Ca2+]i) by the intracellular calcium-sensitive dye, fura-2. Arteries contained up to 5 times more calcium than other soft tissues. Arteries progressively calcified with age whereas other soft tissues did not. Accumulation of calcium with age was essentially extracellular. Hypertension had no effect on age-related arterial calcification. Calcification of the same order as in man was produced in a rat model of arteriosclerosis (vitamin D plus nicotine treatment). In conclusion, as in man, age-linked, organ-specific arterial calcification does occur in rats but its intensity is far less. Arterial calcification of a similar degree to that observed in man can be obtained in rats by hypervitaminosis D plus nicotine.