Relation of nitrite to structural and mechanical adaptation of arteries during postnatal development

Mammalian arteries undergo rapid remodeling during postnatal growth and development. The high wall shear stress at birth is an important mediator of postnatal endothelial nitric oxide (NO) and consequently of growth and remodeling. The objective of this study was to quantify the NO production in relation to geometric and mechanical remodeling of aorta and pulmonary artery during postnatal development. Fifty-one C57BL/6 mice aged from 1 to 33 days were divided into 8 age groups for measurements of nitrite (NO(x)). Systematic measurements of NO(x) in each rings were made in the main pulmonary artery and primary branch as well as along the length of aorta using the combination of a diazo coupling method and high-performance liquid chromatography. The NO(x) data on the aorta were correlated with data on the geometry (diameter, wall thickness) and mechanical properties (stress, strain, elastic modulus) in the same strain of mice under the same conditions. Our findings show postnatal age and vessel size affects the NO production; i.e., the NO(x) decreased with age and diameter. Furthermore, there is a significant positive correlation between strain and NO(x) but negative correlation between both wall thickness and elastic modulus and NO(x) levels. These findings suggest an important interplay between NO(x) and geometric and mechanical remodeling during postnatal growth and development.