AGE RELATED CHANGES IN THE WALLS OF ARCUATE ARTERIES OF KIDNEY: A LIGHT MICROSCOPIC STUDY

Abstract

Although there are many published papers on macro- and microvascularization of the kidney, there has not been a single study that would describe the histological characteristics of the arcuate arteries in specific periods of life. Our motivation to do this study derived from the need to explain the genesis of the ischemic nephropathy and determine the morphological changes on the arcuate arteries. Tissue samples were taken from the kidneys of 50 different cadavers of both sexes. They were divided into five groups, according to their age. The kidneys were of average size and did not show any macroscopic pathological changes. After embedding in paraffin, 5 μm cross-sections through the arteries were prepared. The specimens were analyzed under standard light microscopy, after different staining. The first significant changes are characterized by the widening of the subendothelial layer and the progressive enlargement of the intima. Media gradually shows atrophy, increase of the volume of collagen fibers and reduction of cell numbers. Internal elastic lamina undergoes changes that in time make it wrinkled with denser waves to the point of multiplication. The arcuate arteries, of all the larger intrarenal arteries, undergo the biggest amount of changes. In the beginning, the arcuate arteries suffer a “JET phenomenon”, and that is why the age-related mechanical changes are more prominent in them. The dynamics of the change in their walls accelerates during aging. All described changes that start as a non-atherogenous fibromatosis of the tunica intima is a prerequisite for the development of an atheromatous plaque.