Cholesterol esterase in preglomerular microvessels from normal and cholesterol-fed rabbits

Feeding cholesterol to rabbits produces an atherosclerotic model sharing common metabolic features with the disease in humans, including the vascular lipid accumulation. In coronary vascular cells, this lipid accumulation has been associated with decreased prostacyclin (PGI2) biosynthesis and acid cholesterol esterase activity. Unlike the coronary vascular bed, renal microvasculature appears relatively resistant to atherosclerotic injury. This study examined whether renal microvessels from cholesterol-fed rabbits demonstrated similar metabolic changes in coronary vascular cells. Rabbits were fed either a 0% or 2% cholesterol diet for 1 mo. Similar to coronary vascular cells, in renal microvessels from cholesterol-fed rabbits PGI2 biosynthesis decreased and tissue concentrations of cholesterol and cholesteryl esters increased. However, unlike coronary vascular cells, renal microvascular cholesterol esterase activity increased. Light and electron microscopy revealed sporadic lipid deposits in renal microvessels from cholesterol-fed rabbits and no foam cells or occlusive lesions. In vitro addition of prostanoids to normal renal microvessels had no effect on cholesterol esterase activity. It is inviting to speculate that the increased acid cholesterol esterase activity in renal microvessels from cholesterol-fed rabbits protected them from developing extensive microvascular lesions. These biochemical events may explain the relative resistance of human renal microvessels to the development of occlusive atherosclerotic microvascular lesions.