Vascular Ca overload produced by vitamin D3 plus nicotine diminishes arterial distensibility in rats

In humans, aging produces many structural changes in blood vessels, one of the most pronounced being arterial calcium overload. Simultaneously arteries become increasingly rigid. The slow evolution of the two processes renders it difficult to evaluate the importance of vascular calcium overload in the development of decreased compliance. To gain insight into this relationship, rapid vascular calcium overload was produced by treating young rats with vitamin D3 and nicotine. When rats were allowed 16 days or longer to recover from such treatment, analysis of plasma parameters revealed no overt toxicity, and growth rate was similar to that of controls. Pronounced calcium overload was seen primarily in compliance arteries. Changes in systemic arterial compliance, characteristic impedance, pulse-wave velocity, and carotid compliance all reflected a substantial increase in arterial rigidity. Linear regression analysis revealed significant correlations between the various indicators of arterial distensibility and arterial calcium content. In conclusion, treatment of young rats with vitamin D3 and nicotine may provide a suitable model with which to investigate how calcium overload is involved in the induration of compliance arteries.